Methods and systems for monitoring a service provided over a packet-switched network

ABSTRACT

Methods and systems for monitoring a service provided over a packet-switched network, such as an Internet Protocol television (IPTV) service, an Internet access service, or a voice-over-Internet-Protocol (VoIP) telephony service. Various parameters related to the service (e.g., parameters indicative of packet loss, packet corruption or other packet error) are determined and used to assess various aspects of the service and/or network over which the service is delivered, including a quality of experience (QoE) of subscribers.

FIELD OF THE INVENTION

The invention relates generally to services delivered overpacket-switched networks, such as Internet Protocol television (IPTV),Internet access, and voice-over-Internet-Protocol (VolP) telephonyservices, and more particularly to methods and systems for monitoringsuch services.

BACKGROUND

Various services, including Internet access,voice-over-Internet-Protocol (VolP) telephony, and Internet Protocoltelevision (IPTV), are now being provided over packet-switched networks.

Subscribers to such services enjoy certain advantages, such asinteractive features and/or other additional functionality, which theymay not find in corresponding services provided over traditionalnetworks (e.g., the public switched telephone network (PSTN), cabletelevision, etc.). However, these services are also susceptible tovarious issues which can create service impairments affecting asubscriber's quality of experience (QoE). For example, a subscriber toan IPTV service may experience pixelation, screen freezing, set-top boxcrashes, outages, or other impairments, a subscriber to a VoIP telephonyservice may experience poor voice quality, dropped calls, or otherimpairments, etc.

While certain techniques have been used by service providers in anattempt to mitigate such service impairments, there remains a need forsolutions directed to monitoring these services, including monitoring asubscriber's quality of experience and/or a network's performance inrespect of such services.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a method ofmonitoring performance of a system that comprises a gateway connected toan appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of upstream packets intendedfor an access network having been discarded by the gateway withouthaving been sent to the access network; determining a second parameterindicative of an incidence of gaps between downstream packets receivedby the media application from the gateway; determining, based on atleast the first parameter and the second parameter, a compound parameterindicative of a likelihood that a request for retransmission issued bythe media application will not reach the head-end server; and recordinga log of the compound parameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet unless the missing downstream packetfalls within a gap that exceeds a threshold size. The method comprises:determining a first parameter indicative of an incidence of downstreampackets intended for the media application having been discarded by thegateway without having been sent to the media application; determining asecond parameter indicative of an incidence of gaps between downstreampackets received by the media application from the gateway; determining,based on at least the first parameter and the second parameter, acompound parameter indicative of a likelihood that a gap detected by themedia application will have a size exceeding the threshold size; andrecording a log of the compound parameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet unless the missing downstream packetfalls within a gap that exceeds a threshold size. The method comprises:determining a first parameter indicative of an incidence of downstreampackets having been detected as corrupted; determining a secondparameter indicative of an incidence of gaps between downstream packetsreceived by the media application from the gateway; determining, basedon at least the first parameter and the second parameter, a compoundparameter indicative of a likelihood that a gap detected by the mediaapplication will have a size exceeding the threshold size; and recordinga log of the compound parameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto at least one appliance running a plurality of applications includinga media application and at least one second application. The mediaapplication is configured to detect gaps between downstream packetsreceived from the gateway and to issue to a head-end server a requestfor re-transmission of a missing downstream packet. The methodcomprises: determining a first parameter indicative of an incidence ofdownstream packets having been detected as corrupted; determining asecond parameter indicative of an incidence of gaps between downstreampackets received by the media application from the gateway; determining,based on at least the first parameter and the second parameter, acompound parameter indicative of a degree to which packets related tothe at least one second application are corrupted; and recording a logof the compound parameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of upstream packets sent fromthe gateway to an access network having been detected as corrupted;determining a second parameter indicative of an incidence of gapsbetween downstream packets received by the media application from thegateway; determining, based on at least the first parameter and thesecond parameter, a compound parameter indicative of a likelihood that arequest for retransmission issued by the media application will notreach the head-end server; and recording a log of the compound parameteron a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of downstream packets havingbeen detected as corrupted; determining a second parameter indicative ofan incidence of fixed-duration intervals containing at least onedownstream packet detected as corrupted; determining, based on at leastthe first parameter and the second parameter, a compound parameterindicative of a rate at which requests for retransmission are issued bythe media application; and recording a log of the compound parameter ona storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of downstream packets havingbeen detected as corrupted; determining a second parameter indicative ofan incidence of severely errored intervals, a severely errored intervalbeing a fixed-duration interval containing more than a threshold numberof downstream packets that are detected as corrupted; determining, basedon at least the first parameter and the second parameter, a compoundparameter indicative of an incidence of downstream packets having beencorrupted outside the severely errored intervals; and recording a log ofthe compound parameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of upstream packets sent fromthe gateway to an access network having been detected as corrupted;determining a second parameter indicative of an incidence offixed-duration intervals containing at least one upstream packet sentfrom the gateway that is detected as corrupted; determining, based on atleast the first parameter and the second parameter, a compound parameterindicative of a time taken to service an interactive command provided bya user of the media application; and recording a log of the compoundparameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of upstream packets sent fromthe gateway to an access network having been detected as corrupted;determining a second parameter indicative of an incidence of severelyerrored intervals, a severely errored interval being a fixed-durationinterval containing more than a threshold number of upstream packetssent from the gateway that are detected as corrupted; determining, basedon at least the first parameter and the second parameter, a compoundparameter indicative of an incidence of upstream packets having beencorrupted outside the severely errored intervals; and recording a log ofthe compound parameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of missing downstream packetshaving been retransmitted by the head-end server; determining a secondparameter indicative of an incidence of missing downstream packets forwhich a request for retransmission has been issued; determining, basedon at least the first parameter and the second parameter, a compoundparameter indicative of a success rate of the head-end server inhandling requests for retransmission issued by the media application;and recording a log of the compound parameter on a storage medium.

According to another aspect of the invention, there is provided a methodof monitoring performance of a system that comprises a gateway connectedto an appliance running a media application. The media application isconfigured to detect gaps between downstream packets received from thegateway and to issue to a head-end server a request for retransmissionof a missing downstream packet. The method comprises: determining afirst parameter indicative of an incidence of downstream packets notreaching the media application in time for a content of the mediapackets to be delivered to a user of the media application; determininga second parameter indicative of an incidence of downstream packetshaving been detected as corrupted; determining a third parameterindicative of an incidence of downstream packets intended for the mediaapplication having been discarded by the gateway without having beensent to the media application; determining, based on at least the first,second and third parameters, a compound parameter indicative of afaultiness of a connection between the gateway and the appliance; andrecording a log of the compound parameter on a storage medium.

These and other aspects of the invention will now become apparent tothose of ordinary skill in the art upon review of the followingdescription of embodiments of the invention in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of embodiments of the invention is providedbelow, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 shows an example of a network for providing services, includingan Internet Protocol television (IPTV) service, to subscribers inaccordance with an embodiment of the invention;

FIG. 2 shows an example of a gateway of a subscriber's end-userequipment;

FIG. 3 shows an example of a set-top box of the subscriber's end-userequipment;

FIG. 4 shows an example of a service monitoring entity of the network;

FIGS. 5 and 6 show an example of a process to determine levels ofquality of experience of a subscriber for different periods of time;

FIGS. 7 to 11 show examples of manifestations of a graphical userinterface (GUI) of a monitoring tool;

FIG. 12 shows an example of how a user of the monitoring tool canidentify a root cause of a subscriber's issue; and

FIG. 13 shows an example of a more detailed network architecture overwhich the IPTV service can be delivered.

In the drawings, embodiments of the invention are illustrated by way ofexample. It is to be expressly understood that the description anddrawings are only for the purpose of illustrating certain embodiments ofthe invention and are an aid for understanding. They are not intended tobe a definition of the limits of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows an example of a network 10 for providing services tosubscribers in accordance with an embodiment of the invention. In thisembodiment, one of these services is a television-containing multimediaservice which is provided by a service provider (e.g., atelecommunications company, a cable company, etc.) that controls atleast part of a packet-switched network 13 over which this service isdelivered to subscribers. This control helps to ensure a desired levelof quality of service, security, interactivity and reliability for thesubscribers. The service provider thus has a relationship with eachsubscriber of the television-containing multimedia service in order forthat subscriber to have the service it provides. Other services whichmay be provided over the network 10 may include, for example, anInternet access service and a telephone service.

More particularly, in this embodiment, the television-containingmultimedia service is an Internet Protocol television (IPTV) servicedelivered over the packet-switched network 13 which employs InternetProtocol (IP) routing to convey audio, video and control data. The IPTVservice includes delivery of television (TV) content comprising TVprograms (e.g., live or recorded drama, comedy, news, reality or otherTV shows, movies, sporting events, etc.) currently broadcast on variousTV channels. In this case, the IPTV service also provides time-shiftedTV programming allowing the subscribers to watch TV programs in atime-shifted manner (e.g., a “catch-up” TV feature which replays a TVprogram broadcast hours or days ago, or a “start-over” TV feature whichreplays a current TV program from its beginning). In addition todelivery of currently-broadcast TV content, in this case, the IPTVservice also includes delivery of other audio/video (AN) contenton-demand, such as movies, TV shows, etc., which are not part ofscheduled TV programming but can be selected by the subscribers using avideo-on-demand (VOD) feature.

The network 10 comprises an IPTV system 11 which acquires TV and otherA/V content, processes (e.g., encodes and/or stores) the acquiredcontent, and distributes the content to the subscribers via packetsconveyed over the packet-switched network 13. In this embodiment, theIPTV system 11 comprises a network apparatus 20 that will be referred toas a “super head-end” (SHE) and that is connected to a core network 22,which is also connected to a plurality of network apparatuses 24 ₁-24_(R) that will be referred to as “video hub offices” or “video head-endoffices” (VHOs), each of which is also connected to an access network 26that is also connected to end-user equipment, including, in thisexample, end-user equipment 30 ₁-30 _(N) located at subscriber premises28 ₁-28 _(N) of the subscribers (sometimes referred to as “customerpremises equipment” (CPE)).

The SHE 20 comprises suitable hardware and/or software for implementinga plurality of functional entities, including a processing entity 32 anda routing entity 33.

The processing entity 32 is configured to acquire TV and/or other A/Vcontent and process this content for distribution to the subscribers.More particularly, in this embodiment, the processing entity 32comprises a content acquisition entity 36 which performs a contentingestion process to acquire TV and other A/V content from a pluralityof sources of content 34 ₁-34 _(C). For example, a source of content 34_(x) may comprise an antenna receiving radio broadcast content (e.g., TVprograms on national broadcast channels), a cable (e.g., fiber-optic orcoaxial) conveying broadcast content (e.g., TV programs on specialtychannels), a satellite dish receiving content conveyed by a satellitesignal, storage media (e.g., magnetic or optical disks) storing recordedcontent (e.g., movies or TV shows), or any other source of content(e.g., a wired or wireless link conveying content taken from a livestudio). The content acquisition entity 36 may comprise one or moreencoders (e.g., for MPEG or WM compression) and one or more servers toacquire the content and put it in a format for distribution to thesubscribers. For instance, in this embodiment, IPTV system 11 isimplemented using a Microsoft IPTV™ platform and the content acquisitionentity 36 comprises one or more acquisition servers, referred to as“A-servers”. In other embodiments, the IPTV system 11 may be implementedusing any other suitable platform.

The processing entity 32 may perform other operations in addition to itscontent acquisition operation. For example, in this embodiment, theprocessing entity 32 comprises a digital rights management (DRM) entity42 for encrypting or otherwise processing the acquired content toprevent unauthorized access, copying or conversion to other formats byend-users. As another example, in this embodiment, the processing entity32 comprises an advertisement entity 43 for inserting advertisements insome of the content distributed to the subscribers. As yet anotherexample, in this embodiment, the processing entity 32 comprises anapplications entity 44 for implementing applications that may be invokedby the subscribers (e.g., an electronic program guide (EPG) displayingscheduling information for current and upcoming programming, games orother interactive features, etc.)

Furthermore, in accordance with an embodiment of the invention, and asfurther discussed later, the processing entity 32 comprises a servicemonitoring entity 45 configured to collect and analyze data regardingparameters related to the IPTV service provided to the subscribers inorder to assess various aspects of the IPTV service, including a qualityof experience (QoE) of the subscribers.

In some embodiments, the processing entity 32, including the contentacquisition entity 36, the DRM entity 42, the advertisement entity 43,the applications entity 44 and the service monitoring entity 45, may bepart of a content management system (CMS) used by the service provider.In other embodiments, one or more components of the processing entity 42may be part of one or more other systems used by the service provider.For instance, in some cases, the service monitoring entity 45 may bepart of a network management system (e.g., Operations SupportSystems/Business Support Systems (OSS/BSS)) used by the serviceprovider.

The routing entity 33 is configured to transmit and receive packetspertaining to the IPTV service over the core network 22. For instance,the routing entity 33 may comprise one or more routers or switches.Packets transmitted by the routing entity 33 in a downstream direction(i.e., towards the end-user equipment 30 ₁-30 _(N)) may include packetsconveying TV and/or other A/V content for distribution to thesubscribers. For example, packets conveying TV content currently beingbroadcast may be transmitted as multicast streams, while packetsconveying content selected on-demand may be transmitted as unicaststreams. Packets received by the routing entity 33 in an upstreamdirection (i.e., towards the SHE 20) may include packets conveyingrequests or commands made by the subscribers via the end-user equipment30 ₁-30 _(N) (e.g., TV channel changes, movie selections from the VODfeature, etc). Packets received by the routing entity 33 in the upstreamdirection may also include packets which convey data regardingparameters related to the IPTV service provided to the subscribers andwhich are destined for the service monitoring entity 45.

The SHE 20 may serve a relatively large geographical area. For instance,in some embodiments, the SHE 20 may serve at a national level, in whichcase the broadcast content from the sources of content 34 ₁-34 _(C) mayinclude broadcast content on national TV channels and/or theadvertisements inserted by the advertisement entity 43 may be nationalads.

The core network 22 comprises high-capacity communication links (e.g.,optical fiber links, etc.) which interconnect different components ofthe network 10, including in this case the SHE 20 and the VHOs 24 ₁-24_(R).

The VHOs 24 ₁-24 _(R) are geographically distributed in order to deliverthe IPTV service to subsets of the subscribers in different regions. Inthat sense, the VHOs 24 ₁-24 _(R) can viewed as “regional head-ends”acting as relay points between the SHE 20 and the subscribers. Forinstance, in some embodiments, each of the VHOs 24 ₁-24 _(R) may be usedto deliver the IPTV service to between 100,000 and 1,000,000subscribers.

Each VHO 24 _(x) comprises suitable hardware and/or software forimplementing a plurality of functional entities, including a processingentity 46 and a routing entity 47.

The processing entity 46 of the VHO 24 _(x) is configured to distributeTV and/or other A/V content to the subscribers. More particularly, inthis embodiment, the processing entity 46 comprises a contentdistribution entity 48 for delivering content to respective ones of thesubscribers over the access network 26. Some content distributed by thecontent distribution entity 48 is received from the SHE 20 over the corenetwork 22. In addition, in this embodiment, some content distributed bythe content distribution entity 48 may be acquired at the VHO 24 _(x)from a plurality of sources of content 49 ₁-49 _(F) such that the VHO 24_(x) comprises a content acquisition entity 53. For example, a source ofcontent 49 _(x) may comprise an antenna receiving regional radiobroadcast content (e.g., TV programs on regional TV channels), a cableconveying regional broadcast content (e.g., TV programs on specialtychannels targeted to the regional audience), storage media storingrecorded content (e.g., movies or TV shows targeted to the regionalaudience), or any other source of content. The content acquisitionentity 53 may comprise one or more encoders and one or more servers toacquire the content and put it in a format for distribution to thesubscribers. For instance, in this embodiment where the IPTV system 11is implemented using a Microsoft IPTV™ platform, the content acquisitionentity 53 comprises one or more “A-servers”.

The content distribution entity 48 comprises one or more distributionservers to distribute the content to the subscribers. More particularly,in this embodiment, the content distribution entity 48 comprises one ormore distribution servers configured to distribute TV content receivedfrom the SHE 20 and/or acquired by the VHO 24 _(x) to the subscribers.For instance, in this embodiment where the IPTV system 11 is implementedusing a Microsoft IPTV™ platform, each of these one or more distributionservers is a “D-server”. Also, in this embodiment, the contentdistribution entity 48 comprises one or more on-demand serversconfigured to distribute on-demand content selected by the subscribers(e.g., VOD servers for delivering movies, TV shows or other contenton-demand).

The processing entity 46 of the VHO 24 _(x) may perform other operationsin addition to its content distribution operation. For example, in thisembodiment, the processing entity 46 comprises a DRM entity 62 forencrypting or otherwise processing the content acquired at the VHO 24_(x) to prevent unauthorized access, copying or conversion to otherformats by end-users. As another example, in this embodiment, theprocessing entity 46 comprises an advertisement entity 60 for insertingadvertisements in some of the content distributed to the subscribers. Asyet another example, in this embodiment, the processing entity 46comprises an applications entity 61 for implementing applications thatmay be invoked by the subscribers (e.g., an electronic program guide(EPG) displaying scheduling information for current and upcomingprogramming, games and/or other interactive features, etc).

The routing entity 47 of the VHO 24 _(x) is configured to route packetspertaining to the IPTV service over the access network 26 _(x). Forinstance, the routing entity 33 may comprise one or more routers orswitches. Packets transmitted by the routing entity 47 in the downstreamdirection may include packets conveying TV and/or other A/V content fordistribution to the subscribers. Packets transmitted by the routingentity 47 in the upstream direction may include packets conveyingrequests or commands made by the subscribers (e.g., TV channel changes,movie selections from the VOD feature, etc.). Packets transmitted by therouting entity 47 in the upstream direction may also include packetsconveying requests for retransmission of certain packets conveying TVand/or other NV content that were missing, discarded, corrupted orotherwise not properly received by pieces of equipment of the end-userequipment 30 ₁-30 _(N) at the subscriber premises 28 ₁-28 _(N). Packetstransmitted by the routing entity 47 in the upstream direction may alsoinclude packets which convey data regarding parameters related to theIPTV service provided to the subscribers and which are destined for theservice monitoring entity 45 of the SHE 20.

As mentioned above, the VHO 24 _(x) may be used for delivering the IPTVservice to subscribers in a particular region. For instance, in thisembodiment, while the SHE 20 is used at a national level, the VHO 24_(x) is used at a regional level such that the broadcast content fromthe sources of content 49 ₁-49 _(F) may include broadcast content onregional TV channels and/or the advertisements inserted by theadvertisement entity 60 may be regional ads.

The access network 26 (sometimes referred to as the “last mile”) forms afinal leg delivering connectivity to subscribers and comprises aplurality of communication links that connect end-user equipment ofsubscribers to a remainder of the network 10, including, in thisexample, a plurality of communication links 63 ₁-63 _(N) that reach theend-user equipment 30 ₁-30 _(N) located at the subscriber premises 28₁-28 _(N). In this embodiment, the communication links 63 ₁-63 _(N) areconnected to an access network apparatus 64. In this example, the accessnetwork apparatus 64 is an access multiplexer. More particularly, inthis embodiment, each of the communication links 63 ₁-63 _(N) comprisesa metallic twisted-pair cable (e.g., a copper twisted-pair cable) andthe access multiplexer 64 is a digital subscriber line accessmultiplexer (DSLAM). For instance, in some embodiments, the accessnetwork 26 may implement a fiber-to-the-node or -neighborhood (FUN)architecture such that the DSLAM 64 comprises a FTTN platform (e.g., anAlcatel 7330 Intelligent Services Access Manager (ISAM) Fiber to theNode (FTTN) platform).

The access network 26 also comprises a monitoring entity 58 configuredto perform measurements of certain parameters related to the IPTVservice provided to the subscribers and to report data regarding theseparameters to the service monitoring entity 45, as further discussedlater. In some embodiments, the DSLAM 64 and the monitoring entity 58may be implemented by a common network component. In other embodiments,the DSLAM 64 and the monitoring entity 58 may be implemented by distinctnetwork components linked together by one or more physical links.

The access network 26 may be implemented in various other ways in otherembodiments. For example, in some embodiments, the access network 26 maybe based on another type of fiber-to-the-x (FTTx) architecture, such asa fiber-to-the-curb (FTTC) architecture, or a fiber-to-the-premises(FTTP) architecture (e.g., fiber-to-the-building (FTTB) orfiber-to-the-house (FTTH) infrastructures) in which case the accessmultiplexer 64 may be omitted and the communication links 63 ₁-63 _(N)may comprise optical fiber cables leading to optical network terminals(ONTs) that may be part of the end-user equipment 30 ₁-30 _(N) at thesubscriber premises 28 ₁-28 _(N). As another example, in someembodiments, each of the communication links 63 ₁-63 _(N) may comprise acoaxial cable instead of a metallic twisted-pair cable or optical fibercable.

Various network apparatuses of the network 10, including those of theIPTV system 11 (e.g., the SHE 20 and the VHOs 24 ₁-24 _(R)), thusimplement a head-end system for communicating with the end-userequipment 30 ₁-30 _(N) at the subscriber premises 28 ₁-28 _(N) toprovide the IPTV service and possibly one or more other services (e.g.,an Internet access service, a telephone service, etc.). Various serversof the network 10 which communicate with the end-user equipment 30 ₁-30_(N) at the subscriber premises 28 ₁-28 (e.g., a D-server of the contentdistribution entity 48) may thus be referred to as “head-end servers”.

While the network 10 has a certain configuration in this embodiment, thenetwork 10 may have various other configurations in other embodiments.For example, in some embodiments, one or more additional networkapparatuses, such as a Video Serving Office (VSO), may be providedbetween the VHO 24 _(x) and the access network 26.

The end-user equipment 30 ₁-30 _(N) located at the subscriber premises28 ₁-28 _(N) enable the subscribers at these premises to have the IPTVservice and possibly one or more other services (e.g., an Internetaccess service, a telephone service, etc.).

The end-user equipment 30 _(x) located at the subscriber premises 28_(x) is configured to receive and transmit packets pertaining to theIPTV service over the access network 26 _(x) to allow a user 65 at thesubscriber premises 28 _(x) to be presented with TV content and/or otherAN content on a TV set 66. The TV set 66 may be based on any suitabledisplay technology, including cathode ray tube (CRT), a liquid-crystaldisplay (LCD), plasma, or any other type of TV display technology (e.g.,Digital Light Processing (DLP) or organic light emitting diode (OLED)).In this embodiment, the end-user equipment 30 _(x) can also receive andtransmit packets pertaining to an Internet access service over theaccess network 26 _(x) to allow the user 65 to browse the Internet on apersonal computer 67 (e.g., a desktop computer, a laptop computer,etc.), as well as packets pertaining to a voice-over-IP (VoIP) telephonyservice over the access network 26 to allow the user 65 to engage intelephone calls using a telephone 68 (e.g., a VoIP phone, a a Plain OldTelephony System (POTS) phone equipped with an analog terminal adapter(ATA), or a softphone).

More particularly, in this embodiment, the end-user equipment 30 _(x)comprises a gateway 69 connected to a set-top box (STB) 70 which isconnected to the TV set 66. The STB 70 is an example of an appliancerunning a media application, namely an IPTV application. In thisembodiment, the gateway 69 is also connected to the personal computer 67and the telephone 68. The personal computer 67 is another example of anappliance running a media application, namely an Internet browserapplication. The telephone 68 is yet another example of an appliancerunning a media application, namely a telephony application.

With additional reference to FIG. 2, the gateway 69 comprises suitablehardware and/or software for implementing a plurality of functionalentities, including a processing entity 71 and a routing entity 72. Theprocessing entity 71 comprises a modem 73 for modulating analog carriersignals to encode digital information and to demodulate analog carriersignals to decode information they convey. For example, in thisembodiment where the communication links 63 _(x) comprises a metallictwisted-pair cable, the modem 73 is a DSL modem. The modem 73 may be ofanother type in other embodiments (e.g., a cable modem) depending on thenature of the communication link 63 _(x).

The processing entity 71 of the gateway 69 also comprises a monitoringentity 74 configured to perform measurements of certain parametersrelated to the IPTV service provided to the subscriber at the subscriberpremises 28 _(x) and to report data regarding these parameters to theservice monitoring entity 45, as further discussed later.

The routing entity 72 of the gateway 69 is configured to route packetspertaining to the IPTV service to and from the STB 70 over a physicalcommunication link (i.e., a wired link or wireless link). For instance,the routing entity 72 may comprise a router, switch or other dataforwarding component. Packets transmitted by the routing entity 72 tothe STB 70 may include packets conveying TV and/or other A/V content forpresentation on the TV set 66. Packets transmitted by the routing entity72 over the access network 26 may include packets conveying requests orcommands made by the user 65 (e.g., TV channel changes, selections ofmovies from the VOD feature, etc.). Packets transmitted by the routingentity 72 over the access network 26 may also include packets conveyingrequests for retransmission of certain packets conveying TV and/or otherA/V content that were missing, discarded, corrupted or otherwise notproperly received by the STB 70. Packets transmitted by the routingentity 72 over the access network may also include packets which conveydata regarding parameters related to the IPTV service provided to thesubscriber at the subscriber premises 28, and which are destined for theservice monitoring entity 45.

In this embodiment, the routing entity 72 of the gateway 69 is alsoconfigured to route data pertaining to the Internet access service toand from the personal computer 67, as well to route signals pertainingto the telephone service to and from the telephone 68 (e.g., via asuitable connector depending on whether the phone 68 is a wired POTSequipped with an ATA, a VoIP phone, etc.)

Thus, in this embodiment, the gateway 69 acts as a center or hub forend-user devices at the subscriber premises 28 _(x). More particularly,in this embodiment the subscriber premises 28 _(x) is a residence andthe gateway 69 is a residential gateway (RG) whose functional entities,including the processing entity 71 and the routing entity 72, areintegrated into a terminal installed at a suitable location at theresidence. In other embodiments, the functional entities of the gateway69 may be part of two or more distinct devices interconnected to oneanother via one or more physical links.

The STB 70 comprises suitable hardware and/or software for implementinga plurality of functional entities, including a processing entity 75 anda routing entity 76. The processing entity 75 is configured to process astream of packets conveying TV and/or other A/V content and received viathe routing entity 76 in order to generate A/V signals transmitted tothe TV set 66 for presenting the TV and/or other A/V content to the user65. More particularly, in this embodiment, the processing entity 75comprises a decoder 77 for decoding packets in the received stream ofpackets. Also, in this embodiment, the processing entity 75 comprises aDRM entity 78 to decrypt or otherwise process the received packets toundue the effects of the DRM entity 42 of the SHE 20 and/or the DRMentity 62 of the VHO 24 _(x). A program selector 79 extracts a selectedprogram stream corresponding to a selection made by the user 65 andprovides the packets of the selected program stream to a demultiplexer80, which divides them into elementary streams (voice, audio andcontrol) that are supplied to a compositor 81 creating A/V signalstransmitted to the TV set 66.

The processing entity 75 of the STB 70 is also configured to detectdefects, such as corrupted packets, in the received stream of packets.When possible, the processing entity 75 may correct some of the detecteddefects in the received stream of packets. For example, in thisembodiment, these detection and correction functions may be implementedby the decoder 77 of the processing entity 75.

The processing entity 75 of the STB 70 also comprises a monitoringentity 82 configured to perform measurements of certain parametersrelated to the IPTV service provided to the subscriber at the subscriberpremises 28 _(x) and to report data regarding these parameters to theservice monitoring entity 45, as further discussed later.

The routing entity 76 of the STB 70 is configured to route packetspertaining to the IPTV service to and from the gateway 69 over thephysical communication link linking these components. For instance, therouting entity 76 may comprise a receiver and a transmitter. Packetsreceived by the routing entity 76 in the downstream direction mayinclude packets conveying TV and/or other A/V content for presentationon the TV set 66. Packets transmitted by the routing entity 76 in theupstream direction may include packets conveying requests or commandsmade by the user 65 (e.g., TV channel changes, movie selections from theVOD feature, etc.). Packets transmitted by the routing entity 76 in theupstream direction may also include packets conveying requests forretransmission of certain packets conveying TV and/or other A/V contentthat were missing, discarded, corrupted or otherwise not properlyreceived by the STB 70. Packets transmitted by the routing entity 76 inthe upstream direction may also include packets which convey dataregarding parameters related to the IPTV service provided to thesubscriber at the subscriber premises 28 _(x) and which are destined forthe service monitoring entity 45.

Although in this embodiment the STB 70 is connected to the TV set 66, inother embodiments, functional entities corresponding to the processingentity 75 and the routing entity 76 of the STB 70 may be integrated intothe TV set 66.

As mentioned previously, in this embodiment, the service monitoringentity 45 is configured to collect and analyze data regarding parametersrelated to the IPTV service provided to the subscribers in order toassess various aspects of the IPTV service, including the QoE of thesubscribers.

Referring additionally to FIG. 4, the service monitoring entity 45comprises an interface 57 and a processing entity 59. The interface 57of the service monitoring entity 45 allows data, including dataregarding parameters related to the IPTV service provided to thesubscribers, to be received and transmitted by the service monitoringentity 45. The processing entity 59 is configured to process datareceived or to be transmitted via the interface 57. More particularly,in this embodiment, the processing entity 59 comprises an analysisentity 56 for analyzing the data to derive information indicative of theQoE of the subscribers, as well as a database 83 for storing the dataand the derived information indicative of the QoE of the subscribers, asfurther discussed below.

The parameters related to the IPTV service provided to the subscribers,which will be referred to as “IPTV service parameters”, can take onvarious forms. For instance, Table 1 presents examples of IPTV serviceparameters that may be considered in this embodiment. Various otherexamples of IPTV service parameters may be considered in otherembodiments.

In Table 1, each line corresponds to a respective IPTV service parameterrelated to the IPTV service provided to the subscriber at the subscriberpremises 28 _(x). The first column indicates a name of the respectiveIPTV service parameter. The second column indicates one or more sourcesfrom which the value of the respective IPTV service parameter isdetermined. Generally, the value of the respective IPTV serviceparameter may be determined on a basis of measurements performed by themonitoring entity 82 of the STB 70, the monitoring entity 74 of theresidential gateway 69, the monitoring entity 58 of the access network26, and/or other components (e.g., a D-server of the contentdistribution entity 48 of the VHO 24 _(x)). In some embodiments, thevalue of the respective IPTV service parameter may be obtained from anetwork management system (e.g., an OSS/BSS) used by the serviceprovider and collecting data regarding such measurements. For instance,in this embodiment, the value of the respective IPTV service parametermay be obtained from: a Component Management System (CMS) which collectsdata regarding measurements performed by components at the subscriberpremises 28 _(x), namely the residential gateway 69 and the STB 70(e.g., a “Snapshot” application on the STB 70); an access networksystem, in this case an Access Care™ (AC) system by Nortel, whichcollects data regarding measurements performed by the access network 26and possibly the end-user equipment 30 _(x) at the subscriber premises28 _(x) (e.g., the modem 73 (“far end”—FE) may report on packetsreceived, errors, etc., through a communication channel to the DSLAM 64for record keeping and the DSLAM 64 may perform data reporting andrecording for its side (“near end”—NE), and the Access Care system maycollect the data from the DSLAM 64 related to the NE and FE and provideit to the service monitoring entity 45); and/or a D-server of thecontent distribution entity 48 of the VHO 24 _(x). In other embodiments,the value of the respective IPTV service parameter may be obtained basedon data polled directly from one or more components, such as theresidential gateway 69, the STB 70, etc. The second column may alsoindicate a frequency at which the value of the respective IPTV serviceparameter is obtained. For instance, in this case, the value of therespective IPTV service parameter may be obtained every fifteen minutes(i.e., the value is for a period of fifteen minutes) or daily (i.e., thevalue is for a period of one day). The third column provides adefinition of the respective IPTV service parameter. The fourth columnprovides a technical description of the respective IPTV serviceparameter. The fourth column indicates an importance of the IPTV serviceparameter for the IPTV service or insight that the IPTV serviceparameter can give about the IPTV service.

For example, the IPTV service parameter “DISCARD_PKTS_SENT” refers tothe number of packets intended to be sent by the residential gateway 69to the STB 70 but that have been discarded by the residential gateway 69instead of being sent to the STB 70. The discarded packets may bepackets which have been delayed long enough to be useless. This may becaused, for instance, by shortage of resources or buffer overflow at theresidential gateway 69. In this embodiment, the value of the“DISCARD_PKTS_SENT” parameter is obtained every fifteen minutes by theresidential gateway 69.

As another example, the discarded packets may result in “gaps”, whichcan also be referred to as “holes, in the stream of packets received atthe STB 70 where the discarded packets would normally have been. Atleast some of these holes may result in the STB 70 issuing requests forretransmission of the discarded packets by a D-server of the contentdistribution entity 48 of the VOH 24 _(x). In this example, this appliesto a hole at the STB 70 that is not larger than a threshold size (e.g.,an interval of time corresponding to a number of consecutive missingpackets which would normally occupy the hole). This size may bedetermined, for instance, by evaluating a maximal number of consecutivepackets that can be retransmitted to the STB 70 in time to be reinsertedin the stream of packets by the STB 70 (e.g., based on processing speedsof the STB 70 and the residential gateway 69, transmissioncharacteristics of the communication link 63 _(x), and/or any otherrelevant factor). For example, in this case, a request forretransmission may be issued by the STB 70 when encountering a hole witha size not greater than about 150 ms. For holes greater than 150 ms, theSTB 70 does not issue requests for retransmission. When there is arequest for retransmission, failure of the D-server to retransmit thediscarded packets to the STB 70 in a timely manner may lead topixilation, screen freeze, etc. In this embodiment, the IPTV serviceparameter “RETRY_NUMBER”, which refers to the number of holes smallerthan 150 ms encountered by the STB 70 during a 15-minute interval, ismeasured by the D-server as the number of retransmission requests every15 minutes and is used as the number of holes (“HOLES”) in other IPTVservice parameters. In other embodiments, the number of holes (“HOLES”)may be determined from measurements performed by the STB 70 itself. Forinstance, in some cases, a diagnostic tool implemented by the servicemonitoring entity 45 may query the STB 70 to obtain the number of holes(“HOLES”) as measured by the STB 70.

As yet another example, error conditions may occur in the downstreamdirection from the access network 26 to the residential gateway 69 thatcan cause packets to be corrupted. For instance, packets can bedetermined to be corrupted when they are determined to have failed anerror check performed by the residential gateway 69. In this case, theerror check is a cyclic redundancy check (CRC). Other error checkingtechniques may be used in other cases. In this embodiment, the IPTVservice parameter “FE_CV” refers to far end code violations, which is acount of CRC anomalies received by the residential gateway 69 during a15-minute interval. Depending on their severity, code violations canlead to errored seconds or severely errored seconds and result inretransmission of IPTV packets from a D-Server of the contentdistribution entity 48 of the VOH 24 _(x) to the STB 70. A high “FE_CV”parameter may lead to visual artifacts such as pixilation or screenfreeze and audio impairments such as clipping.

A similar discussion can be made in respect of other ones of the IPTVservice parameters listed in Table 1.

TABLE 1 Source/ Technical IPTV Parameter Frequency DefinitionDescription Importance CRASH_COUNT STB Crash Number of IPTV service LogCrashes outage occurs 15 min This is a count of when the set-top crashevents box crashes. encountered by the set-top box over a 15-mininterval. DISC_RCVD/HOLES CMS | Number of In the event that A value ofinfinity D-Server Discarded holes are means that either 15 min Packetsencountered at all IPTV packets Received divided the set top box, havebeen by Number of requests for successfully Holes retransmissionreceived at the Discarded from the set-top set-top box (i.e. packetsreceived box may not reach no holes). between the set- the D-Server dueA high Discarded top box and the to packets being Packet Residentialdiscarded in the Received-to- Gateway would upstream Holes ratio wouldindicate direction. increase the congestion or probability of theout-of-order requests for re- packets in the transmission upstream fromthe set-top direction. box failing to The reach the D- “DISC_RCVD”Server, and (number of result in visual discarded and/or audio packetsimpairments for received) the IPTV parameter is an customer. example ofa The parameter “DISC_RCVD/ indicative of an HOLES” incidence ofparameter is an upstream example a packets intended compound for theaccess parameter network 26 indicative of a having been likelihood thata discarded by the request for gateway 69 retransmission without havingissued by the been sent to the IPTV application access network runningon the 26. STB 70 will not The “HOLES” reach the D- (number of server ofthe holes) parameter content is an example of distribution entity aparameter 48. indicative of an incidence of gaps between downstreampackets received by the IPTV application running on the STB 70 from thegateway 69. DISC_RCVD/REQ CMS | Number of In the event that A value ofinfinity D-Server Discarded holes are means that either 15 min Packetsencountered at all IPTV packets Received divided the set top box, havebeen by Number of requests for successfully Packets retransmissionreceived at the Requested from the set-top set-top box (i.e. Discardedbox may not reach no holes) or the packets received the D-Server dueholes are more between the set- to packets being than 150 ms (i.e. topbox and the discarded in the no request for re- Residential upstreamtransmission). Gateway would direction. A high Discarded indicate Packetcongestion or Received-to- out-of-order Number of packets in the Packetsupstream Requested ratio direction. would increase The the probabilityof “DISC_RCVD” the requests for (number of re-transmission discardedfrom the set-top packets box failing to received) reach the D- parameteris an Server, and example of a result in visual parameter and/or audioindicative of an impairments for incidence of the IPTV upstreamcustomer. packets intended The for the access “DISC_RCVD/ network 26REQ” parameter having been is an example a discarded by the compoundgateway 69 parameter without having indicative of a been sent to thelikelihood that a access network request for 26. retransmission The“REQ” issued by the (number of IPTV application packets running on therequested) STB 70 will not parameter is an reach the D- example of aserver of the parameter content indicative of an distribution entityincidence of gaps 48. between downstream packets received by the IPTVapplication running on the STB 70 from the gateway 69. DISC_SENT/HOLESCMS | Number of This may be A ratio of 1 would D-Server Discarded causedby strongly suggest 15 min Packets Sent shortage of that the hole(s)divided by resources or encountered at Number of Holes buffer overflow,the set-top box Discarded etc. at the are likely caused packets sentresidential by the packets denote that gateway. IPTV being discardedpackets to be packets being before being sent sent from the discardedwould at the residential residential result in holes at gateway. gatewayto the the set-top box. A ratio of less set-top box (i.e. than 1 ispossible downstream (e.g. more than direction) are one set-top boxdiscarded/ in the home dropped before watching the being sent. same IPTVThe channel). “DISC_SENT” A ratio of greater (number of than us possiblediscarded (e.g. a large hole packets sent) resulting from parameter isan several packets example of a being discarded parameter by theresidential indicative of an gateway). incidence of The downstream“DISC_SENT/ packets intended HOLES” for the IPTV parameter is anapplication example of a running on the compound STB 70 having parameterbeen discarded indicative of a by the gateway likelihood that a 69without having gap detected by been sent to the the IPTV IPTVapplication application running on the running on the STB 70. STB 70will have The “HOLES” a size exceeding (number of a threshold size.holes) parameter is an example of a parameter indicative of an incidenceof gaps between downstream packets received by the IPTV applicationrunning on the STB 70 from the gateway 69. DISC_SENT/REQ CMS | Number ofThis may be A ratio of 1:1 D-Server Discarded caused by would strongly15 min Packets Sent shortage of suggest that the divided by resources orhole(s) Number of buffer overflow, encountered at Packets etc. at thethe set-top box Requested residential are likely caused Discardedgateway. IPTV by the packets packets sent packets being being discardeddenote that discarded would before being sent packets to be result inholes at at the residential sent from the the set-top box, gateway.residential and result in A high ratio of gateway to the requests forre- Discarded set-top box (i.e. transmission of Packet Sent-to-downstream discarded packets Number of direction) are (provided that thePackets discarded/ discarded packets Requested may dropped before has ahole size of be an indication being sent. less than 150 ms). that theholes The caused by the “DISC_SENT” sent packets (number of beingdiscarded discarded are larger than packets sent) 150 ms (i.e. tooparameter is an large/no request example of a for parameterretransmission). indicative of an The incidence of “DISC_SENT/downstream REQ” parameter packets intended is an example of for the IPTVa compound application parameter running on the indicative of a STB 70having likelihood that a been discarded gap detected by by the gatewaythe IPTV 69 without having application been sent to the running on theIPTV application STB 70 will have running on the a size exceeding STB70. a threshold size. The “REQ” (number of packets requested) parameteris an example of a parameter indicative of an incidence of gaps betweendownstream packets received by the IPTV application running on the STB70 from the gateway 69. DISCARD_PKTS_RCVD CMS Number of This parameteris Discarded IPTV 15 min Discarded an indication of packets receivedPackets from the congestion within by the residential set-top box homenetwork, gateway may received by resulting in lead to slow orResidential packets from no response Gateway. home devices duringchannel Discarded being discarded change, or using packets are by theresidential PVR trick modes. packets which gateway arrive out-of-discarded due to order or have unacceptable been delayed delay. longenough to become useless. DISCARD_PKTS_SENT CMS Number of Discardedpackets When IPTV 15 min Discarded sent denote that packets are PacketsSent by packets to be sent discarded by the Residential from theresidential Gateway. residential gateway instead Discarded gateway tothe of being sent to packets are set-top box (i.e. the set-top box,packets which downstream holes will likely have been direction) areresult and delayed long discarded/ requests for re- enough to be droppedbefore transmission to useless; as such, being sent. the D-Server willthey are being This may be be generated by discarded caused by theset-top box. instead of sent shortage of Failure for the D- by theresidential resources or Server to re- gateway. buffer overflow,transmit these etc. at the discarded residential packets to the gateway.IPTV set-top box in a packets being timely manner discarded would willlead to result in holes at pixilation, screen the set-top box. freeze,etc. ERRORS_RCVD CMS Number of Errors Possible errors High error countsDaily Received by the include CRC in the upstream Residential errors,corrupted direction may Gateway. frames, etc. result in slow Thisprovides a received by the channel change daily count of residentialtime and/or transmission gateway from the commands to the errors in theset-top box. These PVR being slow upstream errors are likely orunresponsive. direction (i.e. caused by issues received by the with theinside Residential wiring. Gateway). ERRORS_SENT CMS Number of ErrorsPossible errors IPTV packets Daily Sent by the include CRC containingerrors Residential errors, corrupted will result in Gateway frames, etc.requests for re- This provides a detected by the transmission dailycount of residential from the set-top errors in the gateway prior to boxto the D- IPTV packets sending to the set- Server. If these detected bythe top box. packets are not residential retransmitted and gateway.received by the set-top box in time, visual and/or audio impairmentswill occur. FE_CB AccessCare Far End- This is a count of CorrectedBlocks 15 min Corrected Block the number of should not have This is ablocks at the any direct impact measure of the residential on IPTVnumber of gateway (i.e. customer packets with downstream) experience.errors which which have been have been corrected using corrected in theFEC (forward downstream error correction) direction. during the 15-mininterval. FE_CV AccessCare Far End-Code Code violation is Depending on15 min Violation defined as a count the severity, the This is a of theCRC presence of code measure of anomalies violations leads errorsconditions occurring during to errored of the DSL the accumulationseconds or connection in the period (15-min). severely erroreddownstream Far End Code seconds. direction. Violation refers to Codeviolations CRC anomalies in the received by the downstream Residentialdirection results Gateway. in retransmission of IPTV packets from the D-Server to the set- top box. A high CV value in the downstream may leadto visual artefacts such as pixilation or screen freeze and audioimpairments such as clipping. FE_CV/FE_ES AccessCare Far End Code Thisratio is an A high CV-to-ES 15 min Violations divided indicator of howratio in the by Far End the Code downstream Errored Seconds Violationsin the direction will The “FE_CV” (far downstream likely result in endcode direction are frequent packet violations) distributed duringretransmissions parameter is an the 15-min between the D- example of ainterval. Server and set- parameter top box, with a indicative of anhigh probability incidence of of visual and/or downstream audio packetshaving impairments been detected by being observed the gateway 69 by theIPTV as corrupted. customer. The “FE_ES” (far The “FE_CV/ end erroredFE_ES” seconds) parameter is an parameter is an example of a example ofa compound parameter parameter indicative of an indicative of aincidence of rate at which fixed-duration requests for intervals (e.g.,1- retransmission second intervals) are issued by the containing at IPTVapplication least one running on the downstream STB 70. packet detectedby the gateway 69 as corrupted. FE_CV/FE_SESM AccessCare Far End CodeThis ratio is an A high CV-to- 15 min Violations divided indicator ofhow SES ratio in the by Far End the Code downstream Severely ErroredViolations in the direction Seconds downstream suggests that The “FE_CV”(far direction are CVs are also end code distributed while likelyoccurring violations) the DSL outside of the parameter is an connectionis intervals when example of a reporting severely the DSL parametererrored seconds connection is indicative of an during the 15-minexperiencing incidence of interval. SES condition, downstream and thereis a packets having high probability been detected by that IPTV thegateway 69 customer will as corrupted. experience visual The “FE_SESM”and audio (far end severely impairments errored seconds) during the15-min parameter is an interval. example of a The “FE_CV/ parameterFE_SESM” indicative of an parameter is an incidence of example of aseverely errored compound intervals, where parameter a severelyindicative of an errored interval is incidence of a fixed-durationdownstream interval (e.g., a 1- packets having second interval) beencorrupted containing more outside the than a threshold severely errorednumber of intervals. downstream packets that are detected by the gateway69 as corrupted. FE_CV/HOLES D-Server | Far End Code Code Violations inA high CV-to- AC Violations divided the downstream Holes in the 15 minby Number of direction may lead downstream Holes to packet loss (i.e.direction The “FE_CV” (far holes) at the set- suggests that a end codetop box during the higher probability violations) 15-min interval. ofholes greater parameter is an than 150 ms, example of a which are notparameter being requested indicative of an for incidence ofretransmission. downstream This will result in packets having visual andaudio been detected by impairments. the gateway 69 The “FE_CV/ ascorrupted. HOLES” The “HOLES” parameter is an (number of example of aholes) parameter compound is an example of parameter a parameterindicative of a indicative of an likelihood that a incidence of gaps gapdetected by between the IPTV downstream application packets receivedrunning on the by the IPTV STB 70 will have application a size exceedingrunning on the a threshold size. STB 70 from the gateway 69.FE_CV/PKTS_REQ D-Server | Far End Code The CV-to-Packet A high CV-to- ACViolations divided Requested ratio in Packet 15 min by Number of thedownstream Requested ratio Packets direction is an in the Requestedindication of the downstream Code Violations impact of code directionwould in the violations on IPTV suggest that non- downstream packets(vs. IPTV packets direction may Internet packets) may also be lead topacket during the 15-min impacted. loss at the set- interval. The“FE_CV/ top box. PKTS_REQ” The “FE_CV” (far parameter is an end codeexample of a violations) compound parameter is an parameter example of aindicative of a parameter degree to which indicative of an packetsrelated incidence of to at least one downstream other applicationpackets having running in the been detected by end-user the gateway 69equipment 30x as corrupted. (e.g., the Internet The browser “PKTS_REQ”application (number of running on the packets computer 67) arerequested) corrupted. parameter is an example of a parameter indicativeof an incidence of gaps between downstream packets received by the IPTVapplication running on the STB 70 from the gateway 69. FE_CV_SUB_HOLESD-Server | Far End Code Code Violations in A high value AC Violationsminus the downstream suggests that a 15 min Number of Holes directionmay lead higher probability The “FE_CV” (far to packet loss (i.e. ofholes greater end code holes) at the set- than 150 ms, violations) topbox during the which are not parameter is an 15-min interval. beingrequested example of a for parameter retransmission. indicative of anThis will result in incidence of visual and audio downstreamimpairments. packets having The been detected by “FE_CV_SUB_ the gateway69 HOLES” as corrupted. parameter is an The “HOLES” example of a (numberof compound holes) parameter parameter is an example of indicative of aa parameter likelihood that a indicative of an gap detected by incidenceof gaps the IPTV between application downstream running on the packetsreceived STB 70 will have by the IPTV a size exceeding application athreshold size. running on the STB 70 from the gateway 69.FE_CV_SUB_PKTS_REQ D-Server | Far End Code Code Violations in A highvalue AC Violations minus the downstream suggests that a 15 min. Packetsdirection may lead higher probability Requested to packet loss (i.e. ofholes greater The “FE_CV” (far holes) at the set- than 150 ms, end codetop box during the which are not violations) 15-min interval. beingrequested parameter is an for example of a retransmission. parameterThis will result in indicative of an visual and audio incidence ofimpairments. downstream The packets having “FE_CV_SUB_ been detected byPKTS_REQ” the gateway 69 parameter is an as corrupted. example of a Thecompound “PKTS_REQ” parameter (packets indicative of a requested)likelihood that a parameter is an gap detected by example of a the IPTVparameter application indicative of an running on the incidence of gapsSTB 70 will have between a size exceeding downstream a threshold size.packets received by the IPTV application running on the STB 70 from thegateway 69. FE_ES AccessCare Far End- Far End Errored The presence of 15min Errored Seconds Seconds refers to error seconds is This is a thecount of 1- an indication of measure of second intervals problems witherrors in the DSL during which: one the DSL line for the or more CRCconnection which downstream anomalies, or may impact the direction (i.e.defects such as transmission, from DSLAM to severely errored resultingin re- residential frame (SEF), loss transmission of gateway), and ofsignal (LOS), packets or will affect both loss of power packet loss.IPTV and (LPR) are Uncorrected Internet packets detected at the errorsin IPTV being transmitted Residential packets in the at the time ofGateway (i.e. downstream error condition. downstream). direction maylead to video defects such as pixilation, screen freeze, etc. or audiodefects such as clipping. FE_HBER AccessCare Far End-High A high biterror A DSL 15 min Bit Error Rate rate is an connection with Thisparameter indication of the high bit error rate indicates that apresence of in the high bit error rate disturbers such as downstream isdetected by high noise level in direction will the Residential the DSLlikely have a high Gateway (i.e. connection, as count of codedownstream). detected by the violations, Residential errored seconds,Gateway. etc., which will likely result in visual and audio impairments.FE_SESM AccessCare Far End- This is a count of A DSL 15 min SeverelyErrored 1-second intervals connection with Second during which therehigh count of This measures are: 18 or more severely errored the numberof 1- CRC anomalies, seconds in the sec intervals in or one or moredownstream which the DSL LOS (loss of direction will connection hassignal), SEF likely result in experienced (severe errored visualartefacts severe error frame) or LPR such as pixilation conditions inthe (loss of power) or screen freeze downstream defects are and/or audiodirection. detected at the impairments residential such as clipping.gateway (i.e. downstream). FE_SFR AccessCare Far End- This is a count ofincludes both 15 min Superframe the number of IPTV and Receivedsuperframes (or Internet traffic This is a blocks) received measure ofthe by the residential amount of traffic gateway from the being sentfrom DSLAM during the the DSLAM to 15-min interval the residential (i.e.downstream) gateway (i.e. downstream) FE_SFT AccessCare Far End- This isa count of includes both 15 min Superframe the number of IPTV andTransmitted superframes (or Internet traffic This is a blocks) sent frommeasure of the the residential amount of traffic gateway to the beingsent from DSLAM during the the residential 15-min interval gateway tothe (i.e. upstream). DSLAM (i.e. upstream) FE_UAS AccessCare Far End- ADSL line A DSL 15 min Unavailable becomes connection with Secondunavailable at the unavailable An unavailable onset of 10 downstreamsecond is a count second(s) in the direction will of 1-second contiguousSES likely result in intervals for (severely errored loss of video whichthe DSL seconds). signal (i.e. IPTV line is This parameter serviceoutage) unavailable at shows the count during the 15-min the DSLAM. of1-sec intervals interval. during which the DSL line is unavailable atthe Residential Gateway. ISW AccessCare | This is the cont Packetsdropped Reflects in the CMS | of packets by the home user experienceSnapshot | dropped by the wiring. During a through pixilation 15 mininside wiring of a 15 minute period if and freezing of home there are nothe screen Calculated as packets being The “ISW” follows: reporteddropped parameter is an Total_Packets_ by the local loop example of aExpired-FE_CV- and no packets compound disc_sent-disc_ being dropped byparameter rcvd the modem yet the indicative of a The STB reportfaultiness of a “Total_Packets_ packets being connection Expired”dropped through between the parameter is an the D-Server gateway 69 andexample of a packets requested the STB 70. parameter and packetsindicative of an expired, then the incidence of home wiring isdownstream causing the issue. packets not This measure can reaching theisolate precisely IPTV application which STB is a running on the problemand point STB 70 in time a technician to the for a content of rightdevice the packets to be quickly-therefore delivered to the reducing thetime user 65 of the to resolve the IPTV application trouble running onthe STB 70. For instance, in some cases, an example of the“Total_Packets_ Expired” parameter may be a number of downstream packetsthat were expected by the IPTV application running on the STB 70 withina fixed-duration interval and were either not received before expirationof the fixed-duration interval or were received in corrupted form. The“FE_CV” parameter is an example of a parameter indicative of anincidence of downstream packets having been detected by the gateway 69as corrupted. The “disc_sent” parameter is an example of a parameterindicative of an incidence of downstream packets intended for the IPTVapplication running on the STB 70 having been discarded by the gateway69 without having been sent to the IPTV application running on the STB70. The “disc_rcvd” parameter is an example of a parameter indicative ofan incidence of upstream packets intended for the access network 26having been discarded by the gateway 69 without having been sent to theaccess network 26. Link Resync CMS Link Retrain is a Link retrain canLink retrain will Daily re-sync of the occur when a DSL likely result inDSL connection. connection temporary IPTV encounters service outageseverely errored frame (SEF) defects, high signal-to-noise (SNR) ratio,loss of frames (LOF) or loss of signal (LOS), etc. MAX_HOLE_SIZED-Server Maximum Hole This parameter The closer this 15 min Size is thethe captures the value is to largest hole largest hole (i.e. 150 ms, theencountered packet discard or higher the (measured in ms) loss), up toprobability for by set top box 150 ms, holes greater over the 15-minencountered than 150 ms and interval during a 15-min the more likelyinterval. visual and/or audio impairments will be experienced by theIPTV customer. NE_CB AccessCare Near End- This is a count of CorrectedBlocks 15 min Corrected Block the number of should not have This is ablocks at the any direct impact measure of the DSLAM (i.e. on IPTVnumber of upstream) which customer packets with have been experience.errors which corrected using have been FEC (forward corrected in theerror correction) upstream during the 15-min direction. interval. NE_CVAccessCare Near End-Code Code violation is Depending on 15 min Violationdefined as a count the severity, the This is a of the CRC presence ofcode measure of anomalies violations leads errors conditions occurringduring to errored of the DSL the accumulation seconds or connection inthe period (15-min). severely errored upstream Near End Code seconds.direction. Violation refers to High CVs in the CRC anomalies upstreamreceived by the direction may DSLAM (i.e. lead to slow upstream)response in channel change time or some PVR commands. NE_CV/HOLESD-Server | Near End Code Code violations in A value of 0 AC Violationsdivided the upstream indicates that 15 min by Number of direction mayrequests for all Holes impact the ability holes less than The “NE_CV” ofthe set-top box 150 ms should be (near end code to request re- receivedby the violations) transmission of D-Server. parameter is an packetsfrom the A high CV-to- example of a D-Server during Holes ratioparameter the 15-min indicates a indicative of an interval. higherprobability incidence of of requests for upstream retransmission packetssent not being from the gateway received by the 69 to the accessD-Server. network 26 The “NE_CV/ having been HOLES” detected by theparameter is an access network example of a 26 as corrupted. compoundThe “HOLES” parameter (number of indicative of a holes) parameterlikelihood that a is an example of request for a parameterretransmission indicative of an issued by the incidence of gaps IPTVapplication between running on the downstream STB 70 will not packetsreceived reach the D- by the IPTV server of the application contentrunning on the distribution entity STB 70 from the 48. gateway 69.NE_CV/NE_ES AccessCare Near End Code This ratio is an A high CV-to-ES 15min Violations divided indicator of how ratio in the by Near End theCode upstream Errored Seconds Violations in the direction will The“NE_CV” upstream direction likely result in (near end code aredistributed slow response in violations) during the 15-min channelchange parameter is an interval. time or some example of a PVR commandsparameter during the indicative of an periods when the incidence of DSLline is upstream reporting error packets sent seconds. from the gatewayThe “NE_CV/ 69 to the access NE_ES” network 26 parameter is an havingbeen example of a detected by the compound access network parameter 26as corrupted. indicative of a The “NE_ES” time taken to (near enderrored service an seconds) interactive parameter is an command (e.g., aexample of a channel change parameter or VOD indicative of an command)incidence of provided by the fixed-duration user 65 of the intervals(e.g., 1- IPTV application second intervals) running on the containingat STB 70. least one upstream packet sent from the gateway 69 that isdetected by the access network 26 as corrupted. NE_CV/NE_SESM AccessCareNear End Code This ratio is an A high CV-to- 15 min Violations dividedindicator of how SES ratio in the by Near End the Code upstream SeverelyErrored Violations in the direction Seconds upstream direction suggeststhat The “NE_CV” are distributed CVs are also (near end code while theDSL likely occurring violations) connection is outside of the parameteris an reporting severely intervals when example of a errored seconds theDSL parameter during the 15-min connection is indicative of an interval.experiencing incidence of SES condition, upstream and there is a packetssent high probability from the gateway that slow 69 to the accessresponse time in network 26 channel change having been or PVR detectedby the commands will access network be experienced 26 as corrupted.during the 15-min The “NE_SESM” interval. (near end The “NE_CV/ severelyerrored NE_SESM” seconds) parameter is an parameter is an example of aexample of a compound parameter parameter indicative of an indicative ofan incidence of incidence of severely errored upstream intervals, wherepackets having a severely been corrupted errored interval is outside thea fixed-duration severely errored interval (e.g., a 1- intervals. secondinterval) containing more than a threshold number of upstream packetssent from the gateway 69 that are detected by the access network 26 ascorrupted. NE_CV/PKTS_REQ D-Server | Near End Code Code violations in Ahigh CV-to- AC Violations divided the upstream Packet 15 min by Packetsdirection may Requested ratio Requested impact the ability in theupstream The “NE_CV” of the set-top box direction will (near end code torequest re- likely lead to violations) transmission of unfilled holes,parameter is an packets from the resulting in visual example of aD-Server during and/or audio parameter the 15-min impairments.indicative of an interval. The “NE_CV/ incidence of PKTS_REQ” upstreamparameter is an packets sent example of a from the gateway compound 69to the access parameter network 26 indicative of a having beenlikelihood that a detected by the request for access networkretransmission 26 as corrupted. issued by the The IPTV application“PKTS_REQ” running on the (packets STB 70 will not requested) reach theD- parameter is an server of the example of a content parameterdistribution entity indicative of an 48. incidence of gaps betweendownstream packets received by the IPTV application running on the STB70 from the gateway 69. NE_CV_SUB_HOLES D-Server | Near End Code Codeviolations in A negative value AC Violations minus the upstreamindicates that 15 min Number of Holes direction may most/all packet The“NE_CV” impact the ability retransmission (near end code of the set-topbox requests should violations) to request re- be received by parameteris an transmission of the D-server. example of a packets from the Theparameter D-Server during “NE_CV_SUB_ indicative of an the 15-min HOLES”incidence of interval. parameter is an upstream example of a packetssent compound from the gateway parameter 69 to the access indicative ofa network 26 likelihood that a having been request for detected by theretransmission access network issued by the 26 as corrupted. IPTVapplication The “HOLES” running on the (number of STB 70 will not holes)parameter reach the D- is an example of server of the a parametercontent indicative of an distribution entity incidence of gaps 48.between downstream packets received by the IPTV application running onthe STB 70 from the gateway 69. NE_CV_SUB_PKTS_REQ D-Server | Near EndCode Code violations in A negative value AC Violations minus theupstream indicates that 15 min Number of direction may most/all packetPackets impact the ability retransmission Requested of the set-top boxrequests should The “NE_CV” to request re- be received by (near end codetransmission of the D-server. violations) packets from the The parameteris an D-Serve during “NE_CV_SUB_ example of a the 15-min PKTS_REQ”parameter interval. parameter is an indicative of an example of aincidence of compound upstream parameter packets sent indicative of afrom the gateway likelihood that a 69 to the access request for network26 retransmission having been issued by the detected by the IPTVapplication access network running on the 26 as corrupted. STB 70 willnot The reach the D- “PKTS_REQ” server of the (packets contentrequested) distribution entity parameter is an 48. example of aparameter indicative of an incidence of gaps between downstream packetsreceived by the IPTV application running on the STB 70 from the gateway69. NE_ES AccessCare Near End- Near End Errored The presence of 15 minErrored Seconds Seconds refers to error seconds is This is a the countof 1- an indication of measure of second intervals problems with errorsin the DSL during which one the DSL line for the or more: CRC connectionwhich upstream anomalies, or may impact the direction (i.e. defects suchas transmission, from residential severely errored resulting in re-gateway to frame (SEF), loss transmission of DSLAM), and will of signal(LOS), packets or affect both IPTV loss of power packet loss. andInternet (LPR) are Uncorrected packets being detected at the errors inthe transmitted at the DSLAM (i.e. upstream time of error upstream)direction may condition. lead to slow response in channel change time orsome PVR commands. NE_HBER AccessCare Near End-High A high bit error ADSL 15 min Bit Error Rate rate is an connection with This parameterindication of the high bit error rate indicates that a presence of inthe upstream high bit error rate disturbers such as direction will isdetected by high noise level in likely lead to slow the DSLAM (i.e. theDSL response in upstream). connection, as channel change detected by thetime and some DSLAM. PVR commands. NE_LIA AccessCare Near End-Line TheNE_LIA IPTV service 15 min Initiation Attempt counter is only outagewill occur This is a count of registered by the during DSL line thenumber of DSLAM after a re-sync. DSL line attempt line re-sync has tore-syncs. successfully been completed re- sync has been completed duringthe 15-min time interval. NE_LOLS AccessCare Near End-Loss Loss of Linkmay A loss of link for 15 min of Link Seconds occur due to the DSL Thisis a count of severely errored connection will 1-second frame (SEF)result in IPTV intervals during defects, loss of service outage. whichthere is a signal (LOS), loss loss of link for the of power (LPR), DSLconnection, etc. as measured at the DSLAM over a 15-min interval.NE_SESM AccessCare Near End- This is a count of A DSL 15 min SeverelyErrored 1-second intervals connection with Second during which therehigh count of This measures are: 18 or more severely errored the numberof 1- CRC anomalies, seconds in the sec intervals in or one or moreupstream which the DSL LOS (loss of direction will connection hassignal), SEF likely result in experienced (severe errored slow responsein severe error frame) or LPR channel change conditions in the (loss ofpower) time and/or some upstream defects are PVR commands. direction.detected at the DSLAM (i.e. upstream). NE_SFR AccessCare Near End- Thisis a count of includes both 15 min Superframe the number of IPTV andReceived superframes (or Internet traffic This is a blocks) receivedmeasure of the by the DSLAM amount of traffic from the being sent fromresidential the residential gateway to the gateway to the residentialDSLAM (i.e. gateway during upstream) the 15-min interval (i.e. upstream)NE_SFT AccessCare Near End- This is a count of includes both 15 minSuperframe the number of IPTV and Transmitted superframes (or Internettraffic This is a blocks) sent from measure of the the DSLAM to theamount of traffic residential being sent from gateway during the DSLAMto the 15-min interval the residential (i.e. downstream). gateway (i.e.downstream) NE_UAS AccessCare Near End- By definition, a A DSL 15 minUnavailable DSL line becomes connection with Second unavailable at theunavailable onset of 10 second(s) in the contiguous SES upstream(severely errored direction will lead seconds). to difficulty with Thisparameter channel change shows the count or some PVR of 1-sec intervalscommands during which the during the 15-min DSL line is interval.unavailable at the DSLAM. PACKETS_REQUESTED D-Server Number of This is acount of A high value of 15 min Packets the number of number ofRequested to be packets requested packets retransmitted to by theset-top box requested for the set-top box to be re- retransmission fromthe D- transmitted (for indicates a Server holes smaller than higherprobability 150 ms) from the of visual or audio D-Server duringimpairment. the 15-min interval. PACKETS_SERVICED D-Server Number ofThis is a count of A high value of 15 min Packets the number of numberof requested to be packets being re- packets retransmitted totransmitted from the set-top box the D-Server to a which have beenset-top box during fulfilled by the D- the 15-min Sever interval.PKT_SERV_SUB_PKT_REQ D-Server Packets Serviced This parameter A value of0 15 min minus Packets provides an indicates all Requested indication ofhow requests for successful the D- retransmission (for holes less TheServer is in than 150 ms) “PKT_SERV” fulfilling the have been (packetsrequest for packet fulfilled by the D- serviced) retransmission byServer. parameter is an the set-top box. A negative value example of aindicates that not parameter all requests for indicative of anretransmission incidence of have been missing fulfilled, whichdownstream would result in packets having visual or audio beenimpairments. retransmitted by The the D-server of “PKT_SERV_SUB_ thecontent PKT_REQ” distribution entity parameter is an 48. example of aThe “PKT_REQ” compound (packets parameter requested) indicative of aparameter is an success rate of example of a the D-server of parameterthe content indicative of an distribution entity incidence of 48 inhandling missing requests for downstream retransmission packets forwhich issued by the a request for IPTV application retransmissionrunning on the has been issued STB 70. by the IPTV application runningon the STB 70. REBOOT CMS | 5530 | Number of IPTV service AccessCareReboots outage occurs This is a count of when the the number ofresidential times the gateway reboots. residential gateway rebootsduring the 15-min time interval. RETRY_NUMBER D-Server Number of HolesThis parameter A high value of 15 min encountered at counts the numberretry indicates a the set-top box of holes smaller higher probabilitythan 150 ms of visual or audio encountered by impairment. the set-topbox during the 15-min interval. TOTAL_HOLE_PKTS Snapshot Total Hole Thisis the total This provides an Packets is the number of packetsindication of the total number of for all large holes number of packetsfor all and unfilled holes packets required holes for all live TV forencountered by channels. retransmission. the set-top box For holesgreater than 150 ms, there will be no request for re- transmission, andvisual/audio impairments will be experienced by IPTV customers.TOTAL_PKTS_EXPIRED Snapshot Total Packets This is the total A positivevalue Expired is the number of expired indicates that total number ofpackets (i.e. out- visual and/or packets which of-order packets audiotook too long to or have taken too impairments will arrive at the set-long to arrive) for be experienced top box all large holes and by theIPTV unfilled holes for customer. all live TV channels. TOTAL_PKTS_RCVDSnapshot Total Packets This is a count of Received is the the totalnumber total number of of packets packets received received for all liveby the set-top TV channels by box. the set-top box. TOTAL_PKTS_SENT CMSTotal Number of A measure of the Daily Packets Sent by amount of trafficResidential being sent by the Gateway residential gateway to devicesconnected to the home network.

In this embodiment, the IPTV service parameters may be categorized indifferent ways.

For example, in this embodiment, one way in which the IPTV serviceparameters may be categorized is based on where they are measured (e.g.,in the subscriber premises 28 _(k), in the access network 26, etc.). Inparticular, in this embodiment, some of the IPTV service parameterswhich are used by the service monitoring entity 45 to assess the QoE ofthe subscribers are measured in the access network 26. Morespecifically, in this embodiment, these parameters may be measured bythe monitoring entity 58 of the access network 26. This is particularlyuseful as it can provide insight that could not be otherwise achievedwhen considering IPTV service parameters only measured by the end-userequipment 30 _(x) at the subscriber premises 28 _(x). For example, inthis case, the “NE_CV” parameter, which refers to near end codeviolations reflecting a measure of errors conditions of the DSLconnection in the upstream direction (i.e., towards the DSLAM 64), isbased on measurements performed by the monitoring entity 58 of theaccess network 26.

As another example, in this embodiment, another way in which the IPTVservice parameters may be categorized is by categorizing them as“independent” IPTV service parameters and “compound” IPTV serviceparameters.

An independent IPTV service parameter can be viewed as a metric which isdirectly measured and does not depend on another IPTV service parameter.For instance, one example of an independent IPTV service parameter thatis listed in Table 1 is the “DISCARD_PKTS_SENT” parameter, which refersto the number of packets intended to be sent by the residential gateway69 to the STB 70 but that have been discarded by the residential gateway69 instead of being sent to the STB 70. Another example of anindependent IPTV service parameter that is listed in Table 1 is the“PACKETS_REQUESTED” parameter, which refers to the number of packetsrequested to be retransmitted in requests for retransmission issued bythe STB 70.

A “compound” IPTV service parameter can be viewed as a metric which is afunction of a plurality of IPTV service parameters. A compound IPTVservice parameter may provide insight that cannot be obtained whenconsidering individually the IPTV service parameters on which itdepends. For instance, one example of a compound IPTV service parameterthat is listed in Table 1 is the “DISC_SENT/REQ” parameter, which refersto a ratio of the “DISCARD_PKTS_SENT” parameter (i.e., the number ofpackets intended to be sent by the residential gateway 69 to the STB 70but that have been discarded by the residential gateway 69) and the“PACKETS REQUESTED” parameter (i.e., the number of packets requested tobe retransmitted in requests for retransmission issued by the STB 70). Aratio of 1:1 would strongly suggest that the holes encountered at theSTB 70 are likely caused by the packets being discarded before beingsent by the residential gateway 69. A high ratio may be an indicationthat the holes caused by the packets being discarded are larger than 150ms (i.e., they are too large such that no request for retransmission isissued by the STB 70).

The function defining a given compound IPTV service parameter may takeon various forms. In the examples of compound IPTV service parameterslisted in Table 1, the function defining each compound parameter ispurely arithmetic. More particularly, in these examples, the functiondefining a given compound IPTV service parameter is a division of oneparameter by another or a subtraction of one parameter from another.Thus, in these examples, a given compound IPTV service parameter may bedetermined by determining an arithmetic difference between, or aquotient of, a first operand that comprises a first IPTV serviceparameter on which the given IPTV service compound parameter depends anda second operand that comprises a second IPTV service parameter on whichthe given IPTV service compound parameter depends, as the case may be.Instead of a quotient, a logarithmic difference may be equivalently usedin some cases. The function defining a given compound IPTV serviceparameter may be more complex in other examples.

In this embodiment, a given compound IPTV service parameter may be afunction of two or more other IPTV service parameters which gives anindication of a likelihood of a situation affecting QoE of thesubscriber, possibly causing a service impairment for the subscriber(i.e., video and/or audio impairment, such as pixelation, screenfreezing, etc.).

For example, when packets are dropped and the STB 70 encounters, the STB70 issues requests for retransmission of the dropped packets for holesno greater than 150 ms. Based only on the number of retransmissionrequests received at a D-server of the content distribution entity 48(the IPTV service parameter “RETRY_NUMBER”), one does not know whethersome requests for retransmission sent to the D-Server get dropped beforereaching the D-Server or whether packets retransmitted by the D-serverget dropped before reaching the STB 70. However, a higher value of theIPTV service parameter “DISC_RCVD/HOLES” can indicate a higherlikelihood of requests for retransmission from the STB 70 failing toreach the D-Server and resulting in visual and/or audio impairment forthe subscriber.

As another example, requests for packet retransmission received by aD-server of the content distribution entity 48 indicate that packets aredropped before reaching the STB 70. Based on the number ofretransmission requests alone, one cannot know whether the droppedpackets are causing a service impairment for the subscriber. However, ahigher value of the IPTV service parameter “DISC_SENT/REQ” can indicatethat the holes caused by the packets being discarded are larger than 150ms (i.e. they are too large so that no request for retransmission isissued), thus causing video and/or audio impairment for the subscriber.

Other examples of IPTV service parameters which give indications oflikelihood of situations affecting QoE of the subscribers are presentedin Table 1. Yet other examples may be envisaged in other embodiments.

The service monitoring entity 45 of the SHE 20 collects and processesthe values of the IPTV service parameters to provide insight into theQoE of each of the subscribers. More particularly, based on the valuesof the IPTV service parameters for the subscriber at the subscriberpremises 28 _(x), the service monitoring entity 45 derives informationindicative of the QoE of the subscriber. This information, which will bereferred to as “QoE information”, can be derived in various ways.

For example, in this embodiment, the QoE information for the subscribercomprises a plurality of levels of QoE of the subscriber for differentperiods of time (e.g., a fraction of an hour, an hour, a day, a week, amonth) which provide insight into the QoE of the subscriber at differentdegrees of temporal resolution or granularity. These levels of QoE areattributed by the service monitoring entity 45 based on the values ofthe IPTV service parameters. Since they can be viewed as basicallyrating the QoE of the subscriber, the levels of QoE of the subscriberthat are determined by the service monitoring entity 45 can be viewed as“ratings of QoE”. More particularly, in this embodiment, the QoEinformation comprises a QoE rating for every interval of fifteen minutes(hereinafter referred to as a “15-min QoE rating”), a QoE rating forevery day (hereinafter referred to as a “daily QoE rating”), a QoErating for every week (hereinafter referred to as a “weekly QoErating”), and a QoE rating for every month (hereinafter referred to as a“monthly QoE rating”).

The QoE ratings can be derived in many different ways based on thevalues of the IPTV service parameters for the subscriber. An example ofhow the QoE ratings for the subscriber may be derived in this embodimentwill now be discussed, with additional reference to FIGS. 5 and 6.

a) 15-Min QoE Rating

The values of the IPTV service parameters which are measured every 15minutes are rated to obtain ratings for these parameters. These ratings,which will be referred to as “parameter ratings”, are taken from a setof potential parameter ratings which constitute a parameter ratingscale. The parameter rating scale can take on various forms. Forexample, as shown in Table 2, in this embodiment, the parameter ratingscale includes three potential parameter ratings, namely “green”,“yellow”, and “red”. The value of a given IPTV service parameter for aparticular 15-min interval may be attributed: the “green” parameterrating when it is considered to be in a normal or standard range forthis parameter; the “yellow” parameter rating when it is considered tobe outside the normal or standard range for this particular parameter bya degree which is unlikely to be indicative of a problem affecting thesubscriber's QoE; and the “red” parameter rating when it is consideredto be so outside the normal or standard range for this particularparameter that it likely indicates a problem affecting the subscriber'sQoE.

In this embodiment, a parameter rating is attributed to the value of agiven IPTV service parameter for a particular 15-min interval bycomparing this value to one or more thresholds. Such thresholds may bedetermined by the service provider (e.g., based on conditions whichclearly demonstrate impairments of the IPTV service to the subscriber).Examples of such thresholds are provided in Table 2.

For example, in this case, the value of the “DISCARD_PKTS_SENT”parameter for a particular 15-min interval is compared to a firstthreshold of 200 discarded packets and a second threshold of 9000discarded packets. If the value of the “DISCARD_PKTS_SENT” parameter isless than or equal to 200, it is attributed the “green” parameterrating. If the value of the “DISCARD_PKTS_SENT” parameter is greaterthan or equal to 9000, it is attributed the “red” parameter rating. Ifthe value of the “DISCARD_PKTS_SENT” parameter is between 200 and 9000,it is attributed the “yellow” parameter rating.

The 15-min QoE rating for the subscriber for a particular 15-mininterval is derived on a basis of the parameter ratings of the values ofthe IPTV service parameters for the particular 15-min interval.Specifically, in this example, the 15-min QoE rating for the subscriberfor the particular 15-min interval is taken from a set of potential15-min QoE ratings which forms a 15-min QoE rating scale or range. Forexample, in this embodiment, the 15-min QoE rating scale or rangeincludes four potential 15-min QoE ratings, namely “green”, “yellow”,“red”, and “blue” (which are represented by different cross-hatchingpatterns in FIGS. 5 and 6). A “green” 15-min QoE rating may beattributed when the subscriber's QoE is deemed to be normal or standardfor the particular 15-min interval. A “yellow” 15-min QoE rating may beattributed when the subscriber's QoE is deemed to be affected by arelatively minor issue during the particular 15-min interval. A “red”15-min QoE rating may be attributed when the subscriber's QoE is deemedto be affected by a relatively major issue during the particular 15-mininterval. A “blue” 15-min QoE rating may be attributed when thesubscriber's QoE is deemed to be affected by an issue during a primetimeviewing period, which is determined by the service provider (e.g., 8:00pm to 11:00 pm Eastern and Pacific and 7:00 pm to 10:00 pm Central andMountain from Monday to Saturday, and 7:00 pm to 11:00 pm Eastern andPacific and 6:00 pm to 10:00 pm Central and Mountain on Sunday).

The 15-min QoE rating for the subscriber for the particular 15-mininterval is determined based on criteria defined in terms of theparameter ratings of the values of the IPTV service parameters for theparticular 15-min interval. For instance, in this example:

-   -   If every one of the parameter ratings of the values of the IPTV        service parameters for the particular 15-min interval is the        “green” parameter rating, then the 15-min QoE rating for the        particular 15-min interval is the “green” QoE rating.    -   If any of the parameter ratings of the values of the IPTV        service parameters for the particular 15-min interval is the        “red” parameter rating, then the 15-min QoE rating for the        particular 15-min interval is the “red” QoE rating.    -   If any of the parameter ratings of the values of the IPTV        service parameters for the particular 15-min interval is the        “yellow” parameter rating but none of these parameter ratings is        the “red” parameter rating, then the 15-min QoE rating for the        particular 15-min interval may be the “yellow” QoE rating or the        “red” QoE rating, depending on the number of “yellow” parameter        ratings for the particular 15-min interval. For instance, if the        number of “yellow” parameter ratings for the particular 15-min        interval is below a threshold (e.g., 4 or any other number), the        15-min QoE rating for the particular 15-min interval may be the        “yellow” QoE rating; otherwise, if the number of “yellow”        parameter ratings for the particular 15-min interval is at or        above the threshold, the 15-min QoE rating for the particular        15-min interval may be the “red” QoE rating.    -   If the particular 15-min interval falls within a primetime        viewing period determined by the service provider and any of the        parameter ratings of the values of the IPTV service parameters        for the particular 15-min interval is the “yellow” or “red”        parameter rating, then the 15-min QoE rating for the particular        15-min interval is the “blue” QoE rating.

Various other criteria may be applied in other embodiments to attributethe 15-min QoE rating for the particular 15-min interval.

This approach is applied to each of the ninety-six 15-min intervals in aday in order to obtain ninety-six 15-min QoE ratings for the subscriberfor that day.

The 15-min QoE ratings for the subscriber are examples of intradayratings for periods of time shorter than one day that can be attributed.In other embodiments, intraday ratings for longer or shorter periods oftime can be used (e.g., 5-min QoE ratings, 30-min QoE ratings, 1-hourQoE ratings, 3-hour QoE ratings, etc.).

TABLE 2 Thresholds Measure Red Yellow Green CRASH_COUNT  1 Only Red orGreen   0 DISC_RCVD/HOLES 200+ 101-199 <=100 DISC_RCVD/REQ 200+ 101-199<=100 DISC_SENT/HOLES 200+ 101-199 <=100 DISC_SENT/REQ 200+ 101-199<=100 DISCARD_PKTS_RCVD 9000+   201-8999 <=200 DISCARD_PKTS_SENT 9000+  201-8999 <=200 ERRORS_RCVD 150,000+    Not defined but will <=200 use ablended metric to determine status ERRORS_SENT 150,000+    Not definedbut will <=200 use a blended metric to determine status FE_CB NoThreshold No Threshold No Threshold FE_CV 9,000+   Not defined but will<=200 use a blended metric to determine status FE_CV/FE_ES 100+ 11-99 <=10 FE_CV/FE_SESM 100+ 11-99  <=10 FE_CV/HOLES 100+ 11-99  <=10FE_CV/PKTS_REQ 100+ 11-99  <=10 FE_CV_SUB_HOLES 1000+   11-999  <=10FE_CV_SUB_PKTS_REQ 1000+   11-999  <=10 FE_ES No Threshold No ThresholdNo Threshold Not an indicator Not an indicator on Not an indicator onit's own but it's own but used on it's own but used as a as a combinedused as a combined measure with combined measure with others measurewith others others FE_HBER  5+ 1-4   0 FE_SESM  5+ 1-4   0 FE_SFR NoThreshold No Threshold No Threshold FE_SFT No Threshold No Threshold NoThreshold FE_UAS  5+ 1-4   0 ISW  40+ 11-39  <=10 Link Resync  2 1   0MAX_HOLE_SIZE No Threshold No Threshold No Threshold NE_CB No ThresholdNo Threshold No Threshold NE_CV 9,000+   Not defined but will <=200 usea blended metric to determine status NE_CV/HOLES 100+ 11′99  <=10NE_CV/NE_ES 100+ 11′99  <=10 NE_CV/NE_SESM 100+ 11′99  <=10NE_CV/PKTS_REQ 100+ 11′99  <=10 NE_CV_SUB_HOLES 1000+   11-999  <=10NE_CV_SUB_PKTS_REQ 1,000+    11-999  <=10 NE_ES No Threshold NoThreshold No Threshold Not an indicator Not an indicator on Not anindicator on it's own but it's own but used on it's own but used as a asa combined used as a combined measure with combined measure with othersmeasure with others others NE_HBER  5+ 1-4   0 NE_LIA  1 Either Red or  0 Green nothing in between NE_LOLS  5+ 1-4   0 NE_SESM  5+ 1-4   0NE_SFR No Threshold No Threshold No Threshold NE_SFT No Threshold NoThreshold No Threshold NE_UAS  5+ 1-4   0 PACKETS_REQUESTED 4500+  Notdefined but will  <=70 use a blended metric to determine statusPACKETS_SERVICED No Threshold No Threshold No ThresholdPKT_SERV_SUB_PKT_REQ <=−5  −4 to 0   0 REBOOT  1 Only Red or Green   0RETRY_NUMBER 4500+  Not defined but will  <=70 use a blended metric todetermine status TOTAL_HOLE_PKTS No Threshold No Threshold No ThresholdTOTAL_PKTS_EXPIRED  5+ 1-4   0 TOTAL_PKTS_RCVD No Threshold No ThresholdNo Threshold TOTAL_PKTS_SENT No Threshold No Threshold No Threshold

b) Daily QoE Rating

The daily QoE rating for the subscriber for a particular day isdetermined on a basis of the ninety-six 15-min QoE ratings for thesubscriber for that day. Specifically, in this example, the daily QoErating for the subscriber for the particular day is taken from a set ofpotential daily QoE ratings which forms a daily QoE rating scale orrange. For example, in this embodiment, the daily QoE rating scaleincludes four potential daily QoE ratings, namely “green”, “yellow”,“red”, and “blue”. A “green” daily QoE rating may be attributed when thesubscriber's QoE is deemed to be normal or standard for the particularday. A “yellow” daily QoE rating may be attributed when the subscriber'sQoE is deemed to be detrimentally affected by a relatively minor issueon the particular day. A “red” daily QoE rating may be attributed whenthe subscriber's QoE is deemed to be detrimentally affected by arelatively major issue on the particular day. A “blue” daily QoE ratingmay be attributed when the subscriber's QoE is deemed to bedetrimentally affected by an issue during a primetime viewing period onthe particular day.

The daily QoE rating for the subscriber for the particular day isdetermined based on criteria defined in terms of the ninety-six 15-minQoE ratings for the subscriber for that day. For instance, in thisexample:

-   -   If the number of “yellow” and “red” 15-min QoE ratings for the        particular day is less than or equal to a first threshold, in        this case five, then the daily QoE rating for the particular day        is the “green” daily QoE rating.    -   If the number of “yellow” and “red” 15-min QoE ratings for the        particular day is greater than the first threshold but less than        or equal to a second threshold, in this case twenty, then the        daily QoE rating for the particular day is the “yellow” daily        QoE rating.    -   If the number of “yellow” and “red” 15-min QoE ratings for the        particular day is greater than the second threshold, then the        daily QoE rating for the particular day is the “red” daily QoE        rating.    -   If the number of “blue” 15-min QoE ratings for the particular        day is greater than or equal to a given threshold, in this case        10, then the daily QoE rating for the particular day is the        “blue” daily QoE rating.

The criteria on which the daily QoE rating for the subscriber for theparticular day is determined may also take into account the values ofthe IPTV service parameters which are measured every day. For instance,the value of a given IPTV service parameter which is measured every dayis rated to obtain a parameter rating. As discussed above, and as shownin Table 2, in this embodiment, the “green”, “yellow”, and “red”parameter rating is attributed to the value of the given IPTV serviceparameter for a particular day by comparing this value to one or morethresholds, which are determined by the service provider. As an example,in this case, the value of the “ERRORS_SENT” parameter for a particularday, which refers to the number of errors in the IPTV packets detectedby the residential gateway 69, is compared to a first threshold numberof 200 errors and a second threshold of 150000 discarded packets. If thevalue of the “ERRORS_SENT” parameter is less than or equal to 200, it isattributed the “green” parameter rating. If the value of the“ERRORS_SENT” parameter is greater than or equal to 150000, it isattributed the “red” parameter rating. If the value of the “ERRORS_SENT”parameter is between 200 and 150000, it is attributed the “yellow”parameter rating. In such cases, if any of the parameter ratings of thevalues of the IPTV service parameters for the particular day is the“red” parameter rating, then the daily QoE rating for the particular dayis the “red” daily QoE rating, regardless of what are the 15-min QoEratings for the particular day.

Various other criteria may be applied in other embodiments to attributethe daily QoE rating for the particular day.

This approach is applied to each of the seven days in a week in order toobtain seven daily QoE ratings for the subscriber for that week.

c) Weekly QoE Rating

The weekly QoE rating for the subscriber for a particular week isobtained on a basis of the seven daily QoE ratings for the subscriberfor that week. Specifically, in this example, the weekly QoE rating forthe subscriber for the particular week is taken from a set of potentialweekly QoE ratings which forms a weekly QoE rating scale or range. Forexample, in this embodiment, the weekly QoE rating scale includes fourpotential weekly QoE ratings, namely “green”, “yellow”, “red”, and“blue”. A “green” weekly QoE rating may be attributed when thesubscriber's QoE is deemed to be normal or standard for the particularweek. A “yellow” weekly QoE rating may be attributed when thesubscriber's QoE is deemed to be detrimentally affected by a relativelyminor issue on the particular week. A “red” weekly QoE rating may beattributed when the subscriber's QoE is deemed to be detrimentallyaffected by a relatively major issue on the particular week. A “blue”weekly QoE rating may be attributed when the subscriber's QoE is deemedto be detrimentally affected by an issue during a primetime viewingperiod during the particular week.

The weekly QoE rating for the subscriber for the particular week isdetermined based on criteria defined in terms of the seven daily QoEratings for the subscriber for that week. For instance, in this example:

-   -   If the number of “red” daily QoE ratings for the particular week        is less than or equal to a first threshold, in this case one,        then the weekly QoE rating for the particular week is the        “green” weekly QoE rating.    -   If the number of “red” daily QoE ratings for the particular week        is greater than the first threshold but less than or equal to a        second threshold, in this case three, then the weekly QoE rating        for the particular week is the “yellow” weekly QoE rating.    -   If the number of “red” daily QoE ratings for the particular week        is greater than the second threshold, then the weekly QoE rating        for the particular week is the “red” weekly QoE rating.    -   If the number of “blue” daily QoE ratings for the particular        week is greater than or equal to a given threshold, in this case        3, then the weekly QoE rating for the particular week is the        “blue” weekly QoE rating.

The criteria on which the weekly QoE rating for the subscriber for theparticular week is determined may also take into account the parameterratings of certain IPTV service parameters. For instance, the parameterrating of a given IPTV service parameter may be considered to be ofsufficient importance that, if it is “red” parameter rating, the weeklyQoE rating for the particular week is the “red” weekly QoE rating,regardless of what are the daily QoE ratings for the particular week. Asan example, in this case, if the “REBOOT” parameter, which refers to thenumber of reboots of the residential gateway 69, was attributed the“red” parameter rating anytime during the particular week, the weeklyQoE rating for the particular week is the “red” weekly QoE rating,regardless of what are the daily QoE ratings for the particular week.

Various other criteria may be applied in other embodiments to attributethe weekly QoE rating for the particular week. d) Monthly QoE Rating

The monthly QoE rating for the subscriber for a particular month isobtained on a basis of the daily QoE ratings for the subscriber for thatmonth, in a manner similar to that discussed above in respect of theweekly QoE ratings.

The QoE information for each of the subscribers, including the QoEratings for each of the subscribers, is recorded and stored in thedatabase 83 of the service monitoring entity 45. The database 83 isimplemented by data storage media, which may store data optically (e.g.,an optical disk such as a CD-ROM or a DVD), magnetically (e.g., a harddisk drive, a removable diskette), electrically (e.g., semiconductormemory, floating-gate transistor memory, etc.), and/or in various otherways.

By including the 15-min, daily, weekly, and monthly QoE ratings for thesubscribers, the QoE information stored in the database 83 maintains ahistory of each subscriber's QoE which spans several weeks or months(e.g., a rolling period of six months or more) and which can be analyzedon a 15-min, daily, weekly or monthly basis. This archive can allow theservice provider to identify issues or trends with respect to eachsubscriber's QoE. For example, the historical QoE information can allowthe service provider to identify recurring issues or patternsexperienced by individual subscribers. In order to optimize data storageefficiency, in some embodiments, the historical QoE information storedin the database 83 may be pruned to retain only items of informationpertaining to issues experienced by the subscribers. For instance, onlythe QoE information reflecting “yellow”, “red” or “blue” QoE ratings maybe retained.

The QoE information derived by the service monitoring entity 45 can beused in various ways. Generally, based on the QoE information, theservice monitoring entity 45 provides a service assurance capability toenable the service provider to know how each subscriber is doing, knowwhere and when trouble or issues arise, and therefore reduce the timeand cost to resolve such trouble or issues.

For example, in this embodiment, a user 86 may use a monitoring toolprovided by a user device 87 to gain insight into the QoE of thesubscribers based on the QoE information derived by the servicemonitoring entity 45. For instance, in various cases, the user 86 may bea helpdesk agent or other customer service representative, a technician,a network engineer, an executive or other manager, or some otheremployee of the service provider. The user device 87 comprises an inputportion (e.g., a keyboard, a touchscreen, and/or a mouse or otherpointing device), an output portion comprising a display and possiblyother output components (e.g., a speaker), and a processing portion toprocess data allowing the monitoring tool to be used by the user 86. Inthis embodiment, the user device 87 is a personal computer (e.g., aworkstation, a desktop computer, a laptop computer, etc.). In otherembodiments, the user device 87 may take on other forms (e.g., a mobilephone, a portable technician terminal, etc.).

The monitoring tool is implemented by a monitoring tool application 85.In this embodiment, the monitoring tool application 85 is executed bythe processing entity 59 of the service monitoring entity 45. Themonitoring tool comprises a graphical user interface (GUI) implementedon the user device 87. The user device 87 is connected to the servicemonitoring entity 45 via a communications link 55, which may be a wiredor wireless link.

The monitoring tool enables the user 86 to interact with its GUI inorder to request and be presented with meaningful representations of theQoE information stored in the database 83. The GUI may provide charts,tables, lists and/or any other graphical representation of selectedportions of the QoE information stored in the database 83 that are to bepresented to the user 86.

For instance, FIGS. 7 to 11 show examples of manifestations of the GUIon the computer 86 in this embodiment. In FIG. 7, a set of tablespresents the daily, weekly, and monthly QoE ratings for the subscribersin terms of proportions of the subscribers which had “green”, “yellow”,“red” and “blue” QoE ratings for particulars days, weeks and months. Forinstance, the table indicates that, on May 18, 2010, 84.05% of thesubscribers had “green” daily QoE ratings, 2.45% of the subscribers had“yellow” daily QoE ratings, 6.86% of the subscribers had “red” daily QoEratings, and 6.63% of the subscribers had “blue” daily QoE ratings. InFIG. 8, the daily, weekly, and monthly QoE ratings for a givensubscriber are presented by a calendar which conveys the daily QoErating for each particular day, a list which conveys the weekly QoErating for each particular week, and another list which conveys themonthly QoE rating for each particular month. For instance, the calendarand the lists indicate that the subscriber had “red” daily QoE ratingsfrom Apr. 18 to Apr. 21, 2010, a “green” daily QoE rating on Apr. 22,2010, and a “yellow” daily QoE rating on Apr. 23, 2010, the subscriberhad “red” weekly QoE ratings for the weeks of Apr. 4 and Apr. 11, 2010,and the subscriber had a “red” monthly QoE rating for the month of April2010. In FIGS. 9 to 11, different performance charts are presented.

Various other charts, tables, lists and/or other graphicalrepresentations of selected portions of the QoE information stored inthe database 83 may be presented to the user 86 via the GUI of themonitoring tool (e.g., representations of the 15-min QoE ratings for agiven subscriber, representations of individual ones of the IPTV serviceparameters for a given subscriber, etc.).

Based on the QoE information stored in the database 83, the user 86 maybe alerted to situations affecting the QoE of subscribers. For example,when a particular IPTV service parameter (e.g., a given compound IPTVservice parameters indicative of a likelihood of a situation affectingthe QoE of a subscriber) is attributed a “red” parameter rating or aparticular period of time (e.g., a 15-min interval, a day, a week, or amonth) is attributed a “red” QoE rating, output of the “red” parameterrating or “red” QoE rating on the GUI of the computer 86 provides analert alerting the user 86 to the fact that a situation is potentiallyaffecting the QoE of the subscriber. Other forms of alerts (e.g., pop-upwindows, email messages, etc.) may be issued in other embodiments.

The user 86 can use the monitoring tool provided by the user device 87in order to assess the quality of the IPTV service provided to thesubscribers in general or to specific subscribers, to identify issues inconnection with this service, and establish corrective actions toresolve these issues.

For example, in cases in which the user 86 is a helpdesk agent ortechnician who is handling a subscriber's complaint about the IPTVservice being poor, the QoE information accessible via the monitoringtool provided by the user device 87 may help the helpdesk agent ortechnician diagnose the trouble the subscriber is experiencing and beable to fix it as quickly and efficiently as possible. For instance,FIG. 12 shows how the user 86 can use the monitoring tool via the userdevice 87 to identify the root cause of a subscriber's issue as likelybeing a particular STB at the subscriber's premises. In particular,since the QoE information reflects the status of the access network 26,the user 86 can exclude the DSL connection as the root cause of thesubscriber's issue.

As another example, in some cases, the user 86 may proactively reviewthe QoE information accessible via the monitoring tool provided by theuser device 87 to identify specific subscribers experiencing poorservice quality (e.g., subscribers having a “red” weekly QoE rating) andreach out to them to resolve the issues before these subscribers noticethe poor service or contact the service provider. For instance, the user86 may contact a given subscriber identified as experiencing poorservice to explain the situation and provide a solution to the problem(e.g., instruct the given subscriber to change a cable between the STB70 and the residential gateway 69, advise the given subscriber that atechnician can stop by to resolve the problem, etc.).

Alternatively or additionally, in some embodiments, the processingentity 59 of the service monitoring entity 45 may proactively analysethe QoE information for the subscribers in order to identify specificsubscribers experiencing poor service quality (e.g., subscribers havinga “red” weekly QoE rating) and automatically take actions to resolve theissues before these subscribers notice the poor service and contact theservice provider. For instance, the service monitoring entity 45 maysend a communication (e.g., an email, a voice mail, an internal logcommunication etc.) to a helpdesk agent or a technician to advise of agiven subscriber identified as experiencing poor service to explain thesituation and provide a solution to the problem. As another example, theservice monitoring entity 45 may send a communication (e.g., an email, avoice mail, etc.) to the given subscriber identified as experiencingpoor service to explain the situation and provide a solution to theproblem (e.g., advise the given subscriber that a technician can stop byto resolve the problem, etc.).

While in the examples considered above the user 86 is an employee of theservice provider, in other examples, the user 86 may be the subscriber,who can use the monitoring tool provided by the user device 87 to accessthe QoE information pertaining to his/her subscription.

Another way in which the QoE information derived by the servicemonitoring entity 45 can be used is to assess performance of the network10. Such assessments can give insight into how well the IPTV service isprovisioned by the service provider, isolate chronic issues, serve todevelop better provisioning standards/guidelines and training programsfor technicians, and/or rationalize added investments in connection withthe IPTV service. For example, this may be used to isolate problems byidentifying which network components (e.g., in the SHE 20, in the corenetwork 22, in the access network 26 or in the end-user equipment 30_(x)) are causing these problems. For instance, FIG. 13 shows an exampleof a more detailed architecture over which the IPTV service may bedelivered, with rectangular boxes illustrating potential areas whereissues affecting delivery of the IPTV service may be encountered.

Although in embodiments discussed above the service monitoring entity 45and the QoE information that it derives pertain to an IPTV service, inother embodiments, principles discussed herein may apply to otherservices that can be provided over the packet-switched network 13. Forexample, in other embodiments, principles discussed herein may apply toan Internet access service and/or a VoIP service provided over thepacket-switched network 13. For instance, in such embodiments, a servicemonitoring entity similar to the service monitoring entity 45 may deriveQoE information for subscribers of the Internet access service and/orthe VolP service on a basis of parameters similar to the IPTV serviceparameters discussed above (e.g., with different thresholds being usedin attributing QoE ratings to the parameter values).

While in embodiments considered above, the end-user equipment 30 ₁-30_(N) of the subscribers is located at the subscriber premises 28 ₁-28_(N) and the communication links 63 ₁-63 _(N) of the access network 26include wired links leading to the end-user equipment 30 ₁-30 _(N), inother embodiments, the end-user equipment 30 ₁-30 _(N) of thesubscribers may include mobile wireless devices (e.g., cellular phones)and the communication links 63 ₁-63 _(N) may include wireless links(e.g., cellular links) over which the services are delivered.

Those skilled in the art will appreciate that, in some embodiments, agiven component described herein (e.g., the service monitoring entity45) may comprise one or more pre-programmed hardware or firmwareelements (e.g., application specific integrated circuits (ASICs),electrically erasable programmable read-only memories (EEPROMs), etc.)or other related elements to implement at least some functionality ofthat given component. In other embodiments, a given component describedherein (e.g., the service monitoring entity 45) may comprise a processorhaving access to a memory which stores program instructions forexecution by the processor to implement at least some functionality ofthat given component. The program instructions may be stored on datastorage media that is fixed, tangible, and readable directly by theprocessor. The data storage media may store data optically (e.g., anoptical disk such as a CD-ROM or a DVD), magnetically (e.g., a hard diskdrive, a removable diskette), electrically (e.g., semiconductor memory,floating-gate transistor memory, etc.), and/or in various other ways.Alternatively, the program instructions may be stored remotely buttransmittable to the given component via a modem or other interfacedevice connected to a network over a transmission medium. Thetransmission medium may be either a tangible medium (e.g., optical oranalog communications lines) or a medium implemented using wirelesstechniques (e.g., microwave, infrared or other wireless transmissionschemes).

Although various embodiments of the invention have been described andillustrated, it will be apparent to those skilled in the art thatnumerous modifications and variations can be made without departing fromthe scope of the invention, which is defined in the appended claims.

1-230. (canceled)
 231. A method of monitoring performance of a system that comprises a gateway connected to an appliance running a media application, wherein packets are communicated between the appliance through the gateway and a head-end server, the method comprising: determining a first parameter indicative of a number of packets that, within an accumulation period of time, have been detected as corrupted; determining a second parameter indicative of a count of fixed-duration intervals during the accumulation period of time, containing at least one packet detected as corrupted; determining, based on at least the first parameter and the second parameter, a compound parameter associated with requests for retransmission issued by the media application during the accumulation period of time; determining a level of quality of experience (QoE) of a user of the appliance based on the compound parameter; and outputting the level of QoE through a user interface.
 232. The method defined in claim 231, comprising: recording a log of said compound parameter on a storage medium.
 233. The method defined in claim 231, wherein the first parameter corresponds to a number of packets that, within the fixed-duration interval, have failed an error check carried out by the gateway.
 234. The method defined in claim 233, wherein the error check comprises a cyclic redundancy check.
 235. The method defined in claim 231, wherein the first or second parameter is received from the gateway.
 236. The method defined in claim 231, wherein the first or second parameter is received from the head-end or an access network.
 237. The method defined in claim 231, wherein determining the compound parameter comprises determining a difference between a first operand that comprises the first parameter and a second operand that comprises the second parameter.
 238. The method defined in claim 237, wherein the difference is an arithmetic difference.
 239. The method defined in claim 231, wherein determining the compound parameter comprises determining a quotient of a first operand that comprises the first parameter and a second operand that comprises the second parameter.
 240. The method of claim 231, wherein the appliance comprises a set-top box.
 241. The method of claim 231, wherein the media application comprises a TV application.
 242. The method of claim 231, wherein the gateway comprises a DSL modem.
 243. The method of claim 231, wherein the head end server comprises a D-server.
 244. The method of claim 231, comprising: comparing said compound parameter to a threshold; issuing an alert when said compound parameter exceeds the threshold.
 245. The method of claim 231, comprising: accumulating multiple recordings of said compound parameter; comparing each of said multiple recordings of said compound parameter to a threshold; associating the level of QoE with the period of time based on the number of recordings of said compound parameter that exceed the threshold.
 246. The method of claim 231, wherein the user interface comprises a display configured to display the level of QoE and associated information.
 247. The method of claim 246, wherein the level of QoE falling into a particular range of levels is displayed using a unique color associated with the particular range of levels.
 248. A method of monitoring performance of a system that comprises a gateway connected to an appliance running a media application, wherein packets are communicated between the appliance through the gateway and a head-end server, the method comprising: determining a first parameter indicative of a number of packets that, within an accumulation period of time, have been detected as corrupted; determining a second parameter indicative of a count of severely errored intervals during the accumulation period of time, a severely errored interval being a fixed-duration interval containing more than a threshold number of packets that are detected as corrupted; determining, based on at least the first parameter and the second parameter, a compound parameter indicative of an incidence of packets having been corrupted outside said severely errored intervals; determining a level of quality of experience (QoE) of a user of the appliance based on the compound parameter; and outputting the level of QoE through a user interface.
 249. The method defined in claim 248, comprising: recording a log of said compound parameter on a storage medium.
 250. The method defined in claim 248, wherein the first parameter corresponds to a number of packets that, within a fixed-duration interval, have failed an error check carried out by the gateway.
 251. The method defined in claim 248, wherein the error check comprises a cyclic redundancy check.
 252. The method defined in claim 248, wherein the first or second parameter is received from the gateway.
 253. The method defined in claim 248, wherein determining the compound parameter comprises determining a difference between a first operand that comprises the first parameter and a second operand that comprises the second parameter.
 254. The method defined in claim 253, wherein the difference is an arithmetic difference.
 255. The method defined in claim 248, wherein determining the compound parameter comprises determining a quotient of a first operand that comprises the first parameter and a second operand that comprises the second parameter.
 256. The method of claim 248, wherein the appliance comprises a set-top box.
 257. The method of claim 248, wherein the media application comprises a TV application.
 258. The method of claim 248, wherein the gateway comprises a DSL modem.
 259. The method of claim 248, wherein the head end server comprises a D-server.
 260. The method of claim 248, comprising: comparing said compound parameter to a threshold; issuing an alert when said compound parameter exceeds the threshold.
 261. The method of claim 248, comprising: accumulating multiple recordings of said compound parameter; comparing each of said multiple recordings of said compound parameter to a threshold; associating the level of QoE with the period of time based on the number of recordings of said compound parameter that exceed the threshold.
 262. The method of claim 248, wherein the user interface comprises a display configured to display the level of QoE and associated information.
 263. The method of claim 262, wherein the level of QoE falling into a particular range of levels is displayed using a unique color associated with the particular range of levels.
 264. A method of monitoring performance of a system that comprises a gateway connected to an appliance running a media application, wherein packets are communicated between the appliance through the gateway and a head-end, the method comprising: determining a first parameter indicative of a number of packets that, within an accumulation period of time, have been detected as corrupted; determining a second parameter indicative of a count of fixed-duration intervals during the accumulation period of time, containing at least one packet detected as corrupted; determining, based on at least the first parameter and the second parameter, a compound parameter indicative of a time taken to service an interactive command provided by a user of the media application during the accumulation period of time; determining a level of quality of experience (QoE) of a user of the appliance based on the compound parameter; and outputting the level of QoE through a user interface.
 265. The method defined in claim 264, comprising: recording a log of said compound parameter on a storage medium.
 266. The method defined in claim 264, wherein the first parameter corresponds to a number of packets that, within a fixed-duration interval, have failed an error check carried out by the access network.
 267. The method defined in claim 266, wherein the error check comprises a cyclic redundancy check.
 268. The method defined in claim 264, wherein the first or second parameter is received from the gateway.
 269. The method defined in claim 264, wherein the first or second parameter is received from the head-end server or an access network.
 270. The method defined in claim 264, wherein determining the compound parameter comprises determining a difference between a first operand that comprises the first parameter and a second operand that comprises the second parameter.
 271. The method defined in claim 40, wherein the difference is an arithmetic difference.
 272. The method defined in claim 264, wherein determining the compound parameter comprises determining a quotient of a first operand that comprises the first parameter and a second operand that comprises the second parameter.
 273. The method of claim 264, wherein the appliance comprises a set-top box.
 274. The method of claim 264, wherein the media application comprises a TV application.
 275. The method of claim 264, wherein the gateway comprises a DSL modem.
 276. The method of claim 264, wherein the head-end server comprises a D-server.
 277. The method of claim 264, comprising: comparing said compound parameter to a threshold; issuing an alert when said compound parameter exceeds the threshold.
 278. The method of claim 264, comprising: accumulating multiple recordings of said compound parameter; comparing each of said multiple recordings of said compound parameter to a threshold; associating the level of QoE with the period of time based on the number of recordings of said compound parameter that exceed the threshold.
 279. The method of claim 264, wherein the user interface comprises a display configured to display the level of QoE and associated information.
 280. The method of claim 279, wherein the level of QoE falling into a particular range of levels is displayed using a unique color associated with the particular range of levels. 